Alex the Allegator 4  
The style is certainly interesting, but I'm not sure if it's really necessary to imitate a Game Boy, the limitations of which have always grated. Nonetheless, the game is very good fun and the chip music is nostalgia-inducing.

Icy Tower  
The game that made it cool to program in Allegro :-) A half star knocked off for openly refusing to support Linux, but still a cool game.

Tanky V4  
Excellent old-school title, and has the distinction of being one of the few Linux titles here that hasn't been programmed in such a way that it only works on one distribution. It reminded me of Combat on the Atari 2600. An AI player wouldn't have gone amiss, but the retro feeling is great!