Changed a few things

I didn't change much but I hope it feels more like a game now. Maybe a boring game but a game nevertheless. Now enemy waves reset after 8 enemies and they start back at one. This could theoretically allow you to go infinite thanks to health packs. That's why now health packs disappear after 5 seconds. Also they had the wrong color so I changed them to red. I hope to keep learning and improving this game :)

Ps: I forgot, I changed it so you can fall faster if you press down arrow or w