We just noticed, thanks to TIGSource, that there's a new build of the excellent bunker-building, side-scrolling, robot-smashing, real-time tactical base-managing shooter, Cortex Command. It's filled with fixes, tweaks, and has a new campaign map. I'll chime in with TIGSource's Derek and say that this is the kind of game that makes PC gaming so compelling: it's complicated, challenging, and utterly esoteric in both its ambitions and execution. The hand-drawn art is wondrous, and the huge menu of possibilities it offers for your battles against other base-building players is enthralling. Tricky as hell, but you'll want to take some time to experiment.
Imagine if Worms was an unfinished RTS designed by an artistically-inspired robo-festishist. You'd be in the right kind of ballpark. I'll understand if you don't like this game one bit, but you should at least have a look.