The games difficulty was dampened by having infinite lives, imo. Whenever I got to a new room I would just kill myself and get full life again, no penalty.
You get your life back, but not your armor, that is the penalty. You have 7 hitpoints and 7 points of armor, so a total of 14 hitpoints in a sense. After you die you only get 7 (you might have more if you died by falling into a pit as that ignores your armor and takes HP away directly).
Also, I'm not sure if it was a bug or not, but the last level looked like it displayed the wrong picture. It showed level 3's boss picture flipped.
Temp graphics
Also I found it hard to use most of the non-basic weapons, there were really no applicable situations except the bubbler against the dude that stays on the ceiling in the last level and sometimes in the greenhouse level. I guess I used the boomerangs to kill the robot and final bosses. I never used the shield though.
fakeedit: I think I probably could've used shield on the greenhouse level for the purple things sthat jump between pods or w/e so nvm the weapons were all usable if you think about the situations (I don't, heh)
Well I'll have to agree that the Boomerang and the Bubbler aren't very good at the moment. But the shield is pretty good because it blocks enemy projectiles. I'll change them up a bit probably.