Critical bugfixes

Post-deadline bugfix update.

• The player character was stuck using a single weapon type. Now the weapon type is properly updated based on the successor's stats.
• The enemies weren't scaling with the threat level due to a missing signal link. This was also causing the dragon to never spawn. Both of these issues are fixed.
• Even if the dragon could have spawned, there's a chance that it would not have spawned due to the other enemies saturating the stage's enemy limit. An extra enemy slot just for dragons has been added in order to ensure that the player encounters the dragon.
• A couple of typos were preventing the collected items from actually being applied. These typos have been fixed and the item system is now mostly working as intended.
• If the player fell off the map, they would fall forever. A kill plane has been added below the map to remedy this.