I just downloaded Alien Breed and I really like it! I just wish it saved instead of using passwords.
I have a "quick-save & exit" type feature on my to-do list for the next minor update, which I expect I'll get around to doing in the next couple of months. However I don't plan on having multiple save slots (like RPG type games).
Yeah, quick save and exit is what I was thinking, great job!
EDIT: Also, I think you should add sideways strafing.