Many many fixes.

A productive day fixing some stuff. 

Fixes:

• Dustbin no longer disappears 
• Some enemies have been rebalanced
• Giant Killer now correctly does extra damage to Crab Demons and the last boss. 
• Autosave in the last boss' room is now disabled
• Lots of other minor bugs, typos and oversights fixed

Updates:

• Added new sprites for intro and cutscenes. 
• The Chiton walking sprite is complete (sort of).
• Because Giant Killer now works as advertised, the last boss has been given a power boost.