What would you expect from a game ranking this high in a list of vertical shooters? A renowned brand or company, polished level design, varied modes of game play and sophisticated mechanics? Well, Phoenix by Firi Gamers offers none of that, instead relying on a combination of simplicity, detailed online leaderboards and enemy encounters randomly created on the fly, making for an extremely addictive game.

There are no levels to be found here. Phoenix pushes you through a never-ending corridor, mostly making it a test of survival as you rack up points. Aside from the odd popcorn enemy going down in a single hit you are usually pitted against two or three mid-sized foes or a single big guy spanning the whole screen width, only taking you to the next fight after the current opposition has been dealt with. The background serves no purpose other than offering something to look at, so you'd better not expect any hazards outside of air-bound enemies.

While you are likely to have met every enemy type a few minutes into the game, these aliens ramp up in difficulty as you progress. Where even the huge humanoid robot boss starts out as a pushover only firing off a few rounds of vulcan shot, later on even the smallest enemies can tear you apart, emitting thick curtains of bullets if you aren't quick enough dealing with them. This is where the extremely useful (and also highly satisfying) feature of blowing apart enemy towers comes into play. The bigger the foe, usually the more towers they have attached to them, responsible for all of their firepower. Although simply aiming at your adversaries will eventually tear them down, it's more efficient to aim for whatever turret currently constitutes the greatest threat to you. Some let loose quick bursts of fire aimed directly at you, others emit waves of bullets that only leave a corridor for you to move, while others shoot red orbs that detonate into smaller bullets, spreading in all directions, and so on.

Destroying turrets also turns all of its bullets onscreen into score increasing gold and earns you small health refills and occasionally an item. The latter can either be used immediately or stored for later use by touching the screen with a second finger when picking it up. Items cover everything from full health refills and temporary shields over EMPs, canceling all enemy shots, turning them into even more gold than usual, to various powerful special weapons called “Alpha Strike” such as homing missiles. Other than this, you will encounter weapon upgrades that automatically upgrade your ship's main shots. The damage output of all standard weapons is the same. Two additional ships can be bought for $1 each: the Corsair's defining weapon is a homing missile launcher that needs to be locked onto an enemy for a few moments, but then it wreaks absolute havoc and can target numerous turrets at once if you approach another after having successfully locked onto one. The Mirage's main weapon is an extremely powerful laser that only shoots after you've stayed in a place for a while, making it quite risky to use.

With random enemy composition comes an ever-increasing chance of facing unfair situations, which is probably Phoenix's biggest issue. Make no mistake: skills will get you very far and even seemingly unfair enemies can often be countered by either using an item or tactically targeting the correct turrets. Later on though, enemies sometimes boast weapons that work together just a bit too well, easily leaving you behind in frustration. Fortunately, Firi Games implemented an adaptive and easy to grasp difficulty mechanic. The game always displays between one and five stars, depicting both how aggressive enemies are and how high your score multiplier is. Every time you get hit you lose a star, rendering survival easier while making it harder to score, and clearing the screen of all current enemies nets you an additional star. If you don't want your multiplier to sink too low you can also set a fixed amount of stars that you'll subsequently never fall below.

Once the increasing piles of bullets eventually deplete your lifebar, your score is transmitted to the online leaderboards. While they used to be handled over GameCenter, they are now found in-game, divided into a general worldwide list as well as separate lists for every continent, country, state and city. Working your way up and eventually reaching the top spots in your state or even country helps the game's appeal a whole lot and once the addiction has caught on, you won't be able to visit your grand parents in another city or go on vacation in some distant country without trying to topple said place's record holders, especially as some achievements ask you to be the best in three cities or the best in a state.

The sound effects merely get the job done and the calm music is barely noticeable during the more hectic moments, but the visuals fare a bit better with bright colors and a never changing, yet fitting corridor. Additional eye-candy can be had with Phoenix HD, delivering additional backdrops and an overall improvement in the graphics department. Plus, Phoenix HD is initially free of charge, whereas the original Phoenix costs a single dollar. The latter, however, lets you use the leaderboards right away, while the HD version requires you to invest a dollar into this, but other than that the initial download already is in fact the complete game (bar the two additional ships). No matter which version you should decide to get, Phoenix is easily one of the biggest (positive) surprises you will ever find in the vast land of iOS shooters, unless you can't do without preset level design.

Well before it hit XBLA and PSN, this cranked up Space Invaders had already hit the App Store in July 2009, when it was basically the only one of its kind: A well-engineered shooter among other developers's merely humble attempts at achieving the same. Best of all, despite the myriads of competitors having appeared since then, Space Invaders Infinity Gene still stands as one of the absolute best representatives of its genre on i-devices. If only it wasn't a whoopin' five bucks. It might not seem like much and it is actually cheaper than on the HD consoles, but compared to just about any iOS shooter (or games in general) bar the Cave games, that's a bit on the pricey side of things.

It all begins as innocuously as it did over 30 years ago. Your tiny ship sways left and right only, slowly firing at six rows of equally tiny aliens that slowly make their way down as they return fire. Music and colors are nonexistent, a mothership traverses the screen just above the enemies. Everything appears to be as peaceful and quiet as intergalactic war can ever hope to be. This is where evolution – as it always tends to do – kicks in, drastically changing the course of events. After being treated to a quotation from Charles Darwin – or "the #1 persona non grata in Texas" – the player lays eyes on a brighter screen, classic enemies of different sizes and sturdiness, double the amount of motherships and – behold – colors! Downed motherships leave behind multi-colored molecules which increase your firepower. Although this stage also adds music to the mix, the sum of these changes still wouldn't make for an interesting revival of Space Invaders.

After finishing the first stage, you will have earned enough points to reach the next level of evolution and this is where the game first shows off its potential. The music gets more intense, the background becomes fully colored and animated, the screen can be panned to turn the game into a sidescroller at any time, the action gets fast and trippy, you are given the ability to move freely anywhere on the screen, and enemies go way beyond the classic set of aliens, spreading out to all kinds of big and small organisms, machines and...irrecognizable, abstract objects. Enemies swarm the battlefield in all ways imaginable. They slowly fly in from the sides, apear in rows, rush down from top to bottom, move in arcs, suddenly pop out of thin air, previously at least indicated by thin white lines shuffling along the screen, come in from behind; gone are the old days of crab-like motions merely going left and right, and many foes have also considerably grown in size.

Quickly shooting enemies in succession not only keeps your score multiplier alive and raises it, being the key to high scores, it also rewards you with more evolution points, further unlocking new stages, visual designs, enemies, modes, options, music and ship upgrades. This keeps the experience from growing stale as the constant stream of varied rewards holds many a nice surprise like bosses taken straight from Taito's fishy shooter series Darius, or a mode where your device's music library can be used to generate fitting stages, and there is always something to look forward to.

In terms of controls, Taito has fortunately already hit the mark long before the majority of the genre did, by relying on relative touch controls. They're working great, so since the game remains fair throughout, every loss of a life can be traced back to some mistake on the player's behalf.

The final element to consolidate Space Invaders Infinity Gene's status as a thoroughly excellent title is its presentation. Enemies retain their shades of grey and white, while at the same time boasting increasing variety in design, and backgrounds constantly change, without ever granting the eye any rest. There is always something exploding into white circles, enemy hordes zoom by, and the electronic music further adds to the frantic and wild nature of the whole game. Menus such as the tree of evolution on the other hand are presented a lot more down-to-earth, with white text on a black background and eery, mechanical buzzing, reminiscent of the Metroid series.

Cave's games are all good and fine, but man can hardly live on danmakus alone. Fortunately, this is where the Chinese developed Super Laser comes in, delivering a fantastic, well-rounded shooter in the vein of Raystorm, Super Aleste and others.

As to be expected from a game weighing in at massive 72.1 MB, the graphics and sound offer a wide variety and are basically unrivaled by other small companies on the iPhone with only bigplayers like Cave, EA and Hudson offering similarly pretty shooters. Settings and accompanying enemies not only differ from stage to stage, but they also often change within a level, starting out with more mundane, yet lush forest area and mechanical space ships. Over the course of the six stages (plus a final stage reserved for the final boss) you will traverse caves, organic landscapes that could be inside a huge monster's guts for all we know complete with destructible blisters in the background, fleets of big ships, asteroid fields and more. Enemies range from boring metal balls to squids, unsettling mechanical bugs and dragonflies, basically getting more and more organic as you dig deeper into enemy territory, which is a nice touch. There are a lot of memorable set pieces like when leaving a planet visually heats up both enemies and you and you will find yourself often being reminded of other classic shooters like when a Gradius inspired ball starts swinging its four arms around clockwise or when you manoeuver through a set of big ships destroying their side cannons like in Super Aleste or when a butterfly seems to have escaped from ESPGaluda. These homages never feel like a cheap move, though, but more like a welcome throwback to the heydays of the genre, thanks to not overdoing it and always complementing it with own ideas and styles.

The sound offers a variety just about as strong as the visuals, although maybe not quite reaching its level of quality. Music ranges from being soothing to eery and cheery up to the end of the game where it changes from being all electronic to a rock fest Duke Nukem would be proud of. It is all very well done und suits the atmosphere perfectly, even if it ends up feeling a bit uninspired and forgettable except for the rock part. Sound effects are also doing their job while being unoffensive. It might just be me, but the sound for picking up items highly reminds me of Cave games and at least the sound used for when using the strongest lock-on laser is very rewarding, pakcing a nice punch.

After picking up the correct items two and later four orbs follow your ship, never leaving their positions and never shooting like options in other games would. What they do is protecting you small shots, damaging enemies upon contact and most importantly enabling you to use the Raystorm-esque lock-on laser. Placing the crosshair on an enemy automatically locks on one of your orbs and if you stay on the enemy long enough for all four to lock on, they fire of a powerful laser, which is mandatory for the bosses. And it simply happens to feel good. Detonating a smart bomb destroys two orbs, so it is always a matter of evaluating the situation very closely on whether it is better to waste them, saving some life energy and hoping for a quick restocking or risking to lose some energy without losing any protection due to all orbs staying intact. The weapon system is pretty basic, giving you a choice between a vulcan cannon, another spreading gun and a straight laser. At least none of these makes you tear out your hair if you happen to accidentally pick it up as all of them can be quite powerful when powered up.

Bosses have the nice habit of appealing to one of my guiltiest pleasures: Destroying something bit by bit. Most bosses offer various parts to take aim and destroy, often rewarding you with new parts to rinse and repeat. Instead of merely depleting a long life bar you get to see your progress in a battle way more immediate this way as you tear apart a boss, bursting open its green eyes and making its arms plummet into space (it's not as gruesome as it sounds). Plus, the bosses tend to look extremely nice and varied with a Mushihimesama-esque snake in stage three, a web slinging spider (Axelay?) in stage four and some disgusting dragonfly-like creature in stage six, which clings to a heart. The latter boss doesn't fight himself, rather relying on organic turrets and enemy generators to do the work, reminiscent of the heart bosses in the Contra series.

As great as Super Laser may be, it does have a few issues. Throughout most of the game the challenge stays reasonable, being hard sometimes, though not unfair. Sometimes, however, this takes a change for the worse as enemies don't stay in the upper part of the screen, but come right down at high speed. This wouldn't be anything to complain about if it were only pop corn enemies going down in one hit as is the case in most other shooters. Here it is often enemies withstanding a lot of damage which means cheap deaths if you haven't memorized them coming in. What's more, the boss in stage four takes forever to be defeated and simply isn't fun to battle after the initial minute or so. Also, despite there being four different control methods available, probably next to everybody will use touch controls which sometimes has you obscuring enemies. This isn't an issue for most of the game, but in stage six right before the boss there is a huge pill bug slowly traversing the whole screen, coming in from below. Since it is on the right side of the screen and most players will use their right hand to play, this section becomes more difficult than it should be and the worst part is that the boss fight right after it is also a bit too punishing if you aren't fully upgraded, which in turn is very likely to happen thanks to the pill bug part. At least the final boss isn't affected by this if you know how to deal with him. He uses green homing orbs that stay still and only move to your current position one after another. If you try to keep focusing them and dodge accordingly, you are bound to search for a cleaver to chop of your finger. The trick is to stay calm and get a feeling for their pacing so you don't need to see them at all times and still be able to dodge, just by swaying lightly to the side.

When it comes to danmakus, Cave is the very definition of a behemoth, a Leviathan and a titan. It doesn't really matter if you personally like their games or their design philosophies, you simply have to admit that the Tokyo-based development studio is probably the best and most important driving force behind this shooter subgenre. So what if, say, a single person – let's call him Sunny Tam – tries his hands at the development of a danmaku shooter? While it falls short of Cave's better games in certain regards, it still comes surprisingly close in terms of overall quality, and best of all: It's a lot cheaper, being priced at a mere two bucks.

The ship selection is void of any surprises. You get to choose between a wide shot, a more focused shot and a ship that spreads to both the front and the sides. Something rarely seen in Cave games, however, is the upgrade shop. Using credits earned by high scores you can purchase upgrades in five categories like increased damage, additional continues or additional smart bombs. These perks don't offer anything special, but it's nice to see your ship making growing stronger and it can be argued that it's even for the better, that no crucial abilities and weapons need to be unlocked before one truly stands a chance against any foes.

The level design in all five stages is a bit on the simple side as you'll only battle air-bound enemies projected onto rather abstract backgrounds, but fortunately Sunny took note from Cave once again and implemented a completely optional scoring system. Quickly scraping enemy bullets in succession builds up a score multiplier and, as a nice side effect, it also fills a bar that – once full – activates the extremely powerful trance mode. This mode not only powers up your weapons temporarily, it also grants an additional hit before losing a life. Still, anybody is welcome to simply focus on merely surviving the onslaught of bullet curtains and to stay away from enemy fire as far as possible, rather than – contradictory to any living being's instincts – getting close to it. This freedom of how to approach the game is one of its strongest points, as everything's being cleverly intertwined, without being overly complicated. On one hand, going for a high score is risky, but on the other hand it can also grant the use of trance mode, thus making survival easier again for a while, so it requires a bit more strategic thinking than other shooters.

Another exceedingly strong point would have to be the presentation. The electronic music admittedly is decidedly average, so it's up to the graphics to make up for this and they don't disappoint. As mentioned before, you won't find any oceans to cross, any valleys to dive into, space stations to destroy or fortresses to traverse. Apart from a large moon, the presentation is very abstract, but you won't see anything of the backgrounds most of the time, anyway. Enemies, their bullets and yours, and various other effects like explosions, multiplier pop-up information and the trance mode (de-)activating keep the screen and your eyes busy at all times. Most importantly, Danmaku Unlimited doesn't just look gorgeous, it manages to never trade in playability for visual prowess. Despite all of the color explosions surrounding your ship, you shouldn't lose track of what's happening more than in any other good danmaku-style game.

The controls also leave nothing to be desired. As most good iOS shooters, the game lets you steer your craft via relative touch controls. The inability to deactivate auto-bombing is questionable, but it is at least possible to also activate bombs manually, and trance mode can either be set to being activated automatically once the bar is full or to only being activated upon the press of a button. Another button switches between a wider shot and a more focused one, which brings this article full-swing back to the Cave comparisons: Danmaku Unlimited shares many similarities, while also maintaining an individual identity thanks to unique aesthetics. It's thus worth a look to anybody not averse to bullet hell shooters in general.