Here, you can get help with anything or just chat about the original Commander Keen games.
You need to push the big buttons (using SELECT when standing on them) to zap those bosses, and then avoid them and their projectiles until you get a chance to zap them again. It took me way too long to figure out...poor game design.
Here you go...
I tried to collect all the items, no idea if I did.
Funnily enough, unless you pause the game before ending it you won't know how much points you accumulated.