Bitter Sam by Moon Active seems to be desperate to defy conventions - its main character seems manically depressed, there's no three-star system in sight, and the almost morbid way in which you can fail a level is a shock the first few times it occurs. And yet, despite this, Bitter Sam is unabashedly cute, funny and fun.

Sam's life apparently wasn't doing so well even before a scientist captured and decided to drop him down a deep hole. He'll need to avoid spiked platforms, spinning blades and numerous other hazards while slowly descending in to the Earth's crust. Thankfully he can make use of various piggy's that can be used to break platforms, and if you collect three injections, the piggy will Hulk-out and bash its way through multiple barriers before exploding.

This is just the beginning of what to expect in Bitter Sam as you'll need to collect gems in order to unlock later levels. To do so you'll need to find the optimal path of winding your way through platforms and deploying various power-ups by tilting your iDevice left or right. The basic controls feel rock solid and while some levels may take several attempts to complete, you'll never feel cheated out of a perfect run.

Sadly the game takes a little too long to introduce new elements, opting to reinforce something it has just taught you or revisiting old ground instead of upping the ante. As such the game's difficulty regularly jumps back and forth from challenging to elementary, making it hard to stay focused. Also, considering that gems dictate whether or not you can unlock new areas, it seems odd that you need to unlock individual levels; despite spending time on progressing, it counts for naught as you'll need to replay to collect the gem anyway.

Despite a few missteps, Bitter Sam does its best to make you smile and more often than not it succeeds. Watching Sam dangling on a line with a pig as he sways back and forth with a permanent melancholic expression gives off the perfect mix of oddity and absurdity, which is only further bolstered by the game's amusing power-ups.

If you find most physics-based 'three-star' puzzlers too saccharin for your tastes, Bitter Sam is ready to mix things up and balance things out.