Blast Furnace Activation/Deactivation causes crash

You can't see the F3 cursor while in third person mode.

Slime blocks have odd lighting.

Shortly after respawning, the player's skin turns into a messed up Steve skin. It fixes itself a second later, though.

I open my minecraft launcher, I hit "play" and it starts loading the little green bar at the bottom starts filling up and then the window disappears, and then comes back with a crash report.