I wish it showed you some kind of confirmation (like showing the XP you gained) when you killed somebody in first person, because sometimes it's hard to tell.
I feel like the first person shooting is less accurate than the zoomed out view. Also, crouching while in first person makes it all weird and jumpy when you aim up (and it's not like that when you're standing). I also wish that the keys would be remapped when you're in first person so that W would be forwards, S would be backwards, Space would be jump, and Shift would be crouch (like a normal FPS). Overall, though, I really like the game so far! The soundtrack is amazing!
The upgrades need to be changed so that to upgrade up from another level it's cheaper than upgrading from the start. Like, currently if you can buy a $10 upgrade, and then the next upgrade costs $120, but if you buy the 2nd upgrade right from the start it still costs $120. It needs to be fixed so that if you buy the $10 upgrade the 2nd price goes down to $110.