update 0.2.3

This update exists to fix the last update being a buggy mess. Oops.

~ Reverted the arm rotation code. The "fix" made it way worse.  I'l try to improve it at a later date, but at the moment it isn't game-breaking at least.

~ Fixed the level selector script not loading part 2's levels. Luckily, I didn't need to revert that one.

~ Also improved the hitboxes on some of part 1's enemies.