Tweaks to local multiplayer

Just putting up some patches to improve the experience with multiplayer.

Changes:

-Fixed some weird UI scaling on level 2

-Local Multiplayer now properly supports screenshake per-camera

-Local Multiplayer now properly supports health glitches per-camera

-Removed music for local multiplayer

-Player 2 can now also have slow-ing sound effects, but it's hard to hear since both players share audio, not very well