Robokiller is a Doom-esque style shooter by some of the students in Carnegie Mellon University's Game Creation Society. Created during their spare time, it's pretty much like your average old-school first-person shooter - but with a twist.

Rather than simply hitting a button to fire, the player must draw with their mouse on enemies to kill them. Initially equipped with a handy welding gun, deadly robots can quickly be rendered defunct via gorging out their circuitboards. It's a really nice idea, and of course the game is a little jerky, the music is unbearably repetitive and the keyboard controls are difficult to use à la your favourite shooters from days gone by.

Just be warned - it takes a rather long time to load, so you might find yourself sat contemplating life while you wait. Or not. Give it a play over on the Game Creation site.