SuperTux is an Open Source 2D game where you'll have the control of Tux in an amazing adventure. Tux will walk throughout a good scenery and he has to set his girlfriend free from the hands of the evil forces.
Easy to play, retro look, fast,... it has all necessary ingredients to be one of those games which can give you hours and hours of fun.
Move Tux by using the arrow keys, jump with space and fire with Ctrl. That's all you need to enjoy SuperTux.
If you want a good 2D platform game, don't hesitate, download SuperTux.