Gameplay Demo 4 out now!

Has it really been over a month since the last one?  Whoops.  Blame school for that one.

I've added... a lot in this one.  But I don't really remember exactly what.  For future demos, I plan on doing proper source management and control so I can better document the features.

Regardless, here are some of the highlights:

• added the Orca, a new boss for Ice Fields
• added the shop, a place to visit (between levels in the future) to spend your metals on things
  • also "gambling"
• added upgrades:
  • Static Wool, ARM, Corrosive Vial, Trinity Arsenal, Odd Circle, Bag of Marbles, The Option, Missile Option, Flamethrower Option, Beam Option, Trinity Construct
• reworked Backyard Missile Kit to make it more unique
• added a cooldown for shooting right after you switch weapons
  • this was added because I realized you could shoot two weapons at once by rapidly switching between them lol