When playing Doodle Arcade Shooter on itself one can't help but to wonder what the heck the game's concept is all about. All kinds of colored, realistic looking planes fly across EXTREMELY drab looking black and white paper canyons all while firing off your standard arrays of colored bullets. To say it's not the most homogenous looking game would be quite an understatement, the background and everything else come together as what can only be described as a cacophony of styles. If you have also played Mortal Skies, however, it all starts to make sense. To a certain degree.

On his website, Erwin Jansen – the creator of both – offers Mortal Skies' source code for sale for anybody to – as he puts it – create his own version of Mortal Skies and apparently he took his game and remade with a new look, both to make another quick buck and to show off how easy it apparently is to use the code for a new release. For that he basically just redrew the backdrops to make them look worse than before, ever so slightly altered the player and enemy sprites which is hardly visible in most cases and at least also designed two new enemies for a bit more variety in gameplay. One of these new enemies is a single plane, rushing down in a straight line and giving off a barrage of bullets, whereas the other one is a bigger plane that drops mines. That's already it for changes as everything else has been simply reused, from enemies and music over the story bits and bosses to the achievements and the unlockable planes. Despite the greater variety in enemy design it is hard to recommend this over Mortal Skies due to the inconsistent nature of its visual design and downloading both would be a waste of storage space so you are better off sticking to the original for all intents and purposes.

The concept of pitting shooter players against more or less equally equipped opponents rather than just the usual array of easy prey and overpowered bosses isn't entirely new, as games such as Kingdom Grandprix, Twinkle Star Sprites and Senko no Ronde go to show. All of these had their own ingenious idea of how to successfully sell the concept to players. Kingdom Grandprix fused shoot 'em up action with a racing game, Twinkle Star Sprites combined a shooter with a puzzle game and Senko no Ronde fused a shooter with boredom. Hypercube's Jet Fighter Ace carves itself out yet another niche by infusing a healthy dose of Diablo and social network gaming.

The game requires you to be online at all times in order to offer you a selection of six enemies to choose from. These short battles take no more than about a minute and they are even further divided into three smaller segments. The first third of each battle has you pursue your enemy, trying to deal as much damage as possible while dodging his "countermeasures" (certain weapons) as these would otherwise paralyze you for a brief moment. After a certain amount of time (which can always be seen on a progression bar on the right) you switch places, requiring you to merely dodge the enemy's fire and to hold out until this segment is over as well. It is only here that you can actually die, as every hit depletes the automatically recharging life bar at the top of the screen. Dodging successfully also raises a gold multiplier, but getting hit lowers it a bit. The final third gives you another chance at finally finishing off your opponent before he eventually escapes.

Upon being hit, enemies usually leave behind gold ready for you to pick up and to afterwards invest in various upgrades. Parts like the hull, wings and the reactor have an impact on your craft's attack, defence and speed. Attack and defence should be self-explanatory, but speed doesn't have an effect on how fast you move, since the relative touch controls (the only control method available and highly sufficient for the action) allow for any speed from the start. What it does is determine how long each of the three phases lasts, the higher your speed, the shorter the second third is in comparison to the other two.

Arguably more important than these parts are the two weapon slots each holding one of five different weapon types. Spreaders constantly release piles of relatively weak bullets all over the screen, lasers suffer from a low rate of fire, making up for it in sheer damage and in how the beams stay on screen for a second before vanishing, missiles are heat-seeking, tracers are faster, but weaker lasers that slightly aim themselves and MIRVs are heat-seeking shrapnel missiles, detonating close to the enemy. Countermeasure weapons offer a little less variety: Turrets release slow-moving bullets, mines are even slower and thus easier to dodge and the flamethrower is rather fast and has a broad field of effect, but like every flamethrower in video game history, its weakness lies in its short reach.

Fights earn you experience, ultimately leading to level-ups, which not only slightly raise your stats, but also net you a few crystals (more on that later) and grant access to better versions of your parts available for purchase. The higher the level of the opponent you choose to battle, the more experience you get and retaliating against enemies that attacked you in the previous 24 hours adds another 10% boost to your experience rewards. While all opponents are real players' crafts, they're AI-controlled and the AI isn't exactly all that intelligent, often simply swaying left and right, up and down.

Unfortunately the social networking aspect of Jet Fighter Ace is mostly reduced to the more disputable staples of the "genre" such as the need to wait for your fuel (necessary to engage in battles) to recharge and crystals serving as a rare uber-currency useful for unlocking upgrades quicker than they usually would, for hiring wingmen and for faster fuel refills. Crystals can also be purchased with real money, of course. Other than that it's easy to pretend no other players existing in the game at all. You barely get to know when somebody has attacked you and it doesn't have any negative effect, you never directly play with or against somebody else and although all players are members of either the red or black faction, duking out an eternal fight over the most kills within the last hour to get a gold boost, this doesn't really weigh in, since it's basically impossible to change your faction's status all on your own.

The shooting aspect fares considerably better as long as you are able to draw motivation from levelling-up and improving your equipment. While a lot of battles are either too easy or frustratingly hard to win, a considerable amount of them also requires good dodging skills, precise aiming and different strategies for different enemy weaponries. Jet Fighter Ace is a lot more fun and addictive than it should be, but eventually the fun wears thinner as waiting times grow longer, all weapons have been tested and you realize that there is nothing new to break up the monotony. There are only three backgrounds and the music also repeats over and over and while both the sound and the visuals aren't the worst, they simply could use more variety. In the end, Jet Fighter Ace is worth the initial download (it's often available for free or for a single dollar at most) to tinker around with it for an hour or two, but only the biggest Mafia Wars- and Farmville-nuts will stay hooked for longer and might consider sinking real money into it. While the developers regularly pour out new (free) updates with new content, their forum is filled to the brim with spambot messages linking to Russian non-nude preteen model pages. Don't expect any discussions with other players to unfold there.

Neocell Fighters regards itself as an homage to a couple of classic shooters like Twin Cobra, Raiden and Xevious. At first glance the parallels to at least the latter are obvious with attacks simultaneously launched at ground targets via an always visible crosshair a few centimetres ahead of your craft and at air targets. On second inspection, though, this does absolutely nothing for gameplay as the abundant turrets and tanks are also targeted by your homing missiles which don't need any manual input at all and thus take care of most ground targets with ease.

While a considerable amount of iOS shooters lacks gameplay variety throughout a playthrough, Neocell adds in visual and acoustic monotony. Enemies hardly differ between stages with the standard airborne popcorn enemies even recycling the same formation over and over again. The backgrounds are all comprised of the same tiles, offering only reddish-brown circles, light-brown squares and the occasional purple water. You'll quickly grow bored of the look, which is quite a shame considering the game was heavily altered with update 3.0, mostly depriving it of its original inside-a-huge-monstrosity setting. Enemies and landscapes used to look a lot more varied and – most importantly – organic, whereas now most adversaries are generically robotic and even allegedly organic ones simply are more colorful than others. While the music (alternatively: "the track", since there is just one) loops a little too quickly, it's a pretty charming affair, sounding like a perfect fit for the lighter moments in a Castlevania game or in a (S)NES RPG.

The mechanics are as simple as can be. The scoring system consists of nothing but downing enemies and picking up coins left behind by them, doubling as currency for an upgrade shop. Better weapons cannot be obtained during normal gameplay, but only in said store and luckily the items are cheap enough to be purchased one after another during a single playthrough and there is no option for real money to be used, so it's all fair and square. Don't expect to be given any strategic choices as to what weapons to use and what to buy, as you merely get stronger with each upgrade and cover bigger parts of the screen in bullets. It does certainly feel pretty rewarding to squash enemies with a fully upgraded arsenal, though the last enemy type to be introduced is nearly impossible to be destroyed if not appearing on its own, leaving you no choice but to dodge.

Controls work well for the most part, if it wasn't for one serious gripe: Instead of allowing for smooth, fully analogue movements and positioning, your ship moves digitally on a grid, making it jump from position to position when you only want to move it a millimetre or two. It's not as bad as it might sound and you'll hardly notice it most of the time, but some boss patterns can become more frustrating than they probably were supposed to be, partly also due to your large hit-box.

Neocell has its more than fair share of shortcomings and yet it manages to be a somewhat fun, if unspectacular and mindless romp, mostly thanks to your weapons' satisfying impact, the fair checkpoint system (jump right back into the last level you've unlocked all powered up) and surprisingly decent level design complete with a difficulty curve appropriately rising from yawn-inducing to "Whoah, damn. Dodge, dodge!"

Erwin Jansen once digs out his old code, this time combining the content of Doodle Arcade Shooter and the visuals of the original Mortal Skies with new stages, a couple of new ideas and awfully mediocre music, instead of recycling the old great music as well, for whatever reason. Apart from this, the degree of recycling is borderline insulting, seeing as how all of the fonts, sound effects, backgrounds, enemy designs, options, menus, achievements, upgrade system, pickups, bosses, player planes, the blood splattering effect indicating the loss of a life, and the bonus stage have all been carried over.

Similar to the transition from Mortal Skies to Doodle Arcade Shooter, a few new elements have also found their way into the game, though they're hardly enough to warrant another purchase. The new three-way shot is mostly pointless, as it fires straight to the left and to the right. The fireball shot fares better, but by the end of the day, it's not all that different from any other strong gun shooting upfront, such as the minigun. Ground targets now also include turrets hiding inside of huts or holes in the ground, and foot soldiers standing behind sandbag barricades. The few new backgrounds look horrible (the desert!). While the new tank boss comes highly welcomed, Erwin Jansen must have been intent on repeating one of Mortal Skies most glaring mistakes: Once again the first stage's boss is exceptionally hard to survive in comparison to others. Instead of a single boss, you're fighting a stream of standard planes that come rushing in from the front, equipped with an insanely fast firing machine gun, making it nigh impossible to dodge each and every bullet.

The new wingmen mechanic is neat, from a gameplay perspective, as a bar automatically replenishes over time, allowing you to call in two supportive planes for some massive damage once it has completely filled up. The flipside to this, however, is the incredibly annoying sound alert not only playing once, as soon as you're able to use the wingmen again, but repeatedly every couple of seconds until you've finally had enough and just use it for the hell of it. Stage 4 has you defend a bunch of medic planes, which is a nice diversion, although it amounts to little more than defeating all enemies ASAP and occasionally taking a bullet yourself, rather than letting it hit your companions.

Mortal Skies 2 is about as good as the previous two games and it's a bit longer with eight missions as opposed to six missions, so if you've tried a lite version of one of the prequels and enjoyed what you got there, you might as well just skip their full versions and get Mortal Skies 2 instead, but anybody who's already purchased MS or DAS has no reason whatsoever to shed out money again.