Level 1 is pretty straightforward.
Get used to the power-up system, and the controls.

Well, let's begin :) That little blue cylinder with something orange around, is a 'blue print' for power-ip purposes. And next to it is a 'blue orb', as I mentioned, for you to enter and choose your weapon configuration. It restores some of your energy and clears enemies on-screen when you enter it too. So is pretty handful, when there are no Energy power-ups (they're transparent blobs)

Look mommy! I'm reflected on the green water! :) Aren't those 'space-saucer' like baddies crappy?

This Mid-Boss is boringly stupid and poses no threat wahtsoever. Just stay there, and shoot the shit outta him!

I don't know if these really are Mid-Bosses, they're just so stupid you can't believe it! This one used to have to arms. I blew them off. The lost green bullet below the beam, came from one of its ex-arms. NYAHAHAHA!! DIE!!!!!! YOU SUCKER!!! ermm. Sorry :P

Well, finally. The first-level Boss. First you have to blow the little green section up on its body. It throws crap like hell, like cluster bombs, so be careful. Then....

... He will start firing his machine gun at you, and launching some homing missiles. Just stay still and go down when the missile flies toward you. Easy peasy, let's move to Level 2!!!