I gave Hammerfight a try today, but I only made it through three or four missions before giving up.  It’s a neat enough idea, control a floating machine and move the mouse to swing weapons on it around to hit enemies, but the mouse motions required become really frustrating really fast, especially with a small space to work in, a mouse that likes to catch on the edges of things, and a game UI that likes to cover up important bits of the screen during the fight.  Not a keeper.