Fixed some bugs and rebalanced some shop items

After playing with some friends, I encountered some bugs in the multiplayer mode. So in this update, I hopefully fixed them all. If you still encounter some, let me know!

Also, I found the quota scaling to be a little too difficult which causes player to not be able to experiment with different upgrades. I lowered the difficulty a little to account for that. Also some shop upgrades were a little too strong so I also reduced their impact a little.