Rough around the edges and with some very obtrusive if understandable ad banners, War in Space will occasionally demand some forgiveness but it's still a quite fun Tower Defense style game.
Rather than having to deal with multiple lanes, the action is simple. Enemy spacecrafts come from the right hand side of the screen, aiming to take out the planet to the left of the screen. A series of slots on the bottom dictate where one can place defensive turrets. These turrets tend to be a mixture of rockets or lasers, each with advantages and disadvantages to the arsenal. Often, it's a matter of choosing speed or force, with a combination of both being the best solution.
Each turret can be upgraded with coins also used to buy one-off boosts such as a flurry of mines or missile attacks, proving ideal when close to being overrun by enemy invaders. As is often the way, in-app purchases can be used to buy more coins but it's possible to complete stages without them. What's not so pleasant is the bombardment of adverts, but these can be easily circumvented for a $0.99 in-app purchase and the game feels well worth that.
It's possible to unlock all of the levels of the game, 20 in all, via an in-app purchase but I wouldn't recommend it - purely because the game is hardly substantial to begin with. On the plus side, by unlocking them all it does open up a survival mode for the determined souls out there.
War in Space is certainly kind of rough, with a retro style that feels sometimes more dated than nostalgic, but it's a fun ride. At times it feels a little like certain levels must be tackled in a particular way rather than offering flexibility, but it's mostly forgivable. It won't set the App Store on fire with its imagination or style, but it's certainly dependable.