Gratuitous Tank Battles is the result of experimentation with the tower defence genre, yielding a strategy game where you attack as much as entrench. Experimentation with units means players can make their own machines and turn them on their foes. And experimentation with AI means the computer can use your creations against you in an endless arms race of tanks, mechs and laser-toting Tommies.
Fittingly for a world where the Great War never ended, very few units will make it through: hundreds will die in a pointless bloodbath to gain just a few inches of ground. But GTB's fields of death are thrilling to die on, over and over again. The key is asymmetry. Playing a map as the defender gives you a traditional tower defence game, where you plop down turrets and defensive forces to try to stem the incoming tide. Attacking is more like the 'reverse' tower defence of Anomaly: Warzone Earth – you decide the order and routes of your units in the hope of breaking through the cyber-Kaiser's defences.
But what really makes both sides of this top-down strategiser stand out is the unit customisation. Much like Positech's previous game, Gratuitous Space Battles, you build your own units. Pick a hull and add whatever weapons, armour and engines you desire. Trenches full of riflemen giving you trouble? Put together a heavily armoured flamethrower tank to smoke them out.
But there's a catch: any unit you design can also be used by the game's superb, adaptive AI. So that flame tank you treasured as an attacker is now a rolling fortress on the defence. A long-range laser turret will fry an enemy before he gets close, but next time out you'll have to deploy some heavily shielded mecha-men to take it down. You're forced into a continual arms race with yourself and, in keeping with the WW1 theme, one you can never quite win.
The campaign is a little on the short side with only a handful of official maps available, but you can browse an abundance of user-made missions. Budding Field Marshalls can edit maps and upload their forces online, custom units and all, for anyone to defend against. The ease with which these challenges can be shared and downloaded extends your playtime immeasurably.
More problematic is the game's tendency to crash faster than a biplane over Belgium. Starting or finishing a map, as well as saving and deleting units, can potentially result in a short sharp trip to your desktop. You'll rarely lose any significant progress this way, but it still makes for a frustrating experience.
But these are minor issues that continuous updates will fix, and they don't take the shine off an otherwise excellent game. Gratuitous Tank Battles is both challenging and strategic, and the clever use of AI and customisation results in a successful bout of experimentation.
[ Since this review was published in the magazine, several patches have indeed addressed numerous stability issues. Positech say they are not "aware of anyone getting random crashes in the game under any circumstances right now." ]