A few decent games using the Allegro libraries were released recently, the best one being Membrane Massacre(screenshot below)
Membrane Massacre is a strange arcade game where the player must take control of a spaceship and gun down hordes of bacteria. There are plenty of levels, destructable terrain, weapons and upgrades for you to mess around with, the gameplay just gets a little tedious.
Brutalo Deluxe is a mundane clone of Soldat, just one level, 5 weapons and very tedious gameplay. It might kill a couple of minutes of boredom.
Peacefighter is a top down shooter made only in 72 hours. The game only features a couple shades of colors and is quite difficult. It has a built in level generator and quite a few weapons, its worth checking out.