Re: parasite in city
I beat stage 3; however, it took me like 5 attempts. Make sure you skip as many enemies as you can during the stages without the face huggers as to not to waste bullets. On the face hugger stages, I found it pivotal to jump onto the platforms asap so you can kill the face huggers right away. The platforms are mostly safe from the green bugs they spawn. Also, they can't attack you while you're hanging onto a ledge. A good way to kill most of the green bugs is to wait until they jump at you, then shoot them while they're at eye level. You can step on them pretty soon after.
I hope this helps!
Btw, thank you for the game dot_slave! It's simply splendid, especially for your first game. I've played a lot of platformer, action type H-games and rarely do they meet this type of quality. Much appreciated!