SlamBots

There's a Monty Python sketch in which a writer comes up with a joke which is so funny that anybody who hears it immediately dies.

It sometimes feels as though the indie game development community is working towards a similar end - a game so addictive that anybody who plays it gets trapped in an endless, blinking, starvation-inducing feedback loop of effort and reward.

SlamBots is the latest experiment in this murderous project, combining ultra-hip pixel-art graphics and retro sound with accessible grind-based arcade bounce-'em-up gameplay to produce a game that paradoxically manages to be both unique and formulaic.

At first you might mistake it for a Doodle Jump clone, because the sprite under your control - initially a Cyborg Ninja - jumps automatically, and you have to tilt your handset to steer him onto platforms, and onto the heads of robots to kill them.

But there's a significant difference: the aim isn't to climb, but to bounce around on the ground and the same four platforms until something finally kills you.

Holding a finger down on the screen puts you in slam mode, and if you hit a robot in this state you'll get more points - but your slam meter diminishes as you use it, so you have to be sparing if you want to keep your combo going.

In each attempt you accumulate both points and coins. The points determine how far up the Game Center leaderboards you sit, and the coins allow you to buy upgrades, including new characters, new slamming machines, new backdrops, and upgrades to the various power-ups you can collect during rounds.

As with Jetpack Joyride, Ridiculous Fishing, and other games of this kind, SlamBots contains two occasionally contradictory goals. You can either play in a straightforward way, killing baddies and trying to score points, or you can concentrate on earning enough money to buy things that may help you to score more points - or make more money - next time.

The difference between SlamBots and those games is that the money comes painfully slowly, and therefore so do the upgrades. You can expect to get 50 or so coins out of a good round when you first start playing, while most of the upgrades cost more than a thousand. And when you do save up enough to buy, for example, the Cyborg Orc, the benefit is incremental at best.

The money-making side of SlamBots is a bit of a thankless grind, with none of the cash bonanzas that make similar games so rewarding.

Thankfully, the actual gameplay side of it fares better. The power-ups and super-bouncy platforms come at just the right random intervals, the challenge is stiff without being excessively frustrating, and the action ramps up at a nice pace.

A good round generally means a flowing, satisfying, combo-accumulating spell in the zone, and - crucially - whenever you die it takes absolutely no time to start again.

SlamBots comes frustratingly close to being genuinely worthwhile, but it withholds too much in the hope that you'll make up the difference from your own pocket. The search for a fatal casual game goes on.