New Runner Shooter enemy - keeps distance, fires fast green Firebolts, harder to kill, appears from Mission #5
Multiple Shooters per mission - expect crossfire and flanks
New player spawn locations - better map variety and early flow
AI spawner improvements - tighter control of timing, distance, and mix
Chem Gun - performance pass and a counting bug fix
Fireball optimization - lighter tick, improved hit handling
Update #18 - The Shooter
Source: Steam Community (opens in a new tab)