Code:
use the 'L' key as fire button
Ah,... got it now

Cool game,... it looks a lot like liero, but you already mentioned that.

The way you handle weapons selection in the game is a bit odd, not sure how you should solve that though... perhaps a different button to cycle through the weapons instead of two seperate buttons. You could also use images to display the choosen weapon.

I'd personally add a little gravity to the guys. Right now you can almost jump (fly) to any part of the map.

I really like what you did sofar, keep up the good work!