Version 2.0 - Gameplay Overhaul

• Reworked character upgrade system
◦ Every upgrade now counts individually.
◦ Every character now has a unique upgrade pool.
◦ Get 1 Reroll when level up by default.
• Reworked weapon system: you may only pick weapons at the pregame screen
• Added the Extreme difficulty and a new enemy type.
• Now difficulties and weapons need to be unlocked by playing.