Beta v4.0:

Combine enemies can now drop ammo.

Removed bonus starting ammo satchel stashes.

Healing weapons now start with 1.5x amount of meds.

Beta v3.2:

Added a damage resistance to marines against energy balls from Combine Elites' AR2.

Removed flamer requirements and set the biomass to be able to be ignited by explosions and flares.

Beta v3.1:

Ammo Satchels now start with 5 stashes instead of 3.

Beta v3.0:

Added an accuracy mechanic where Combine units that use PDW or AR2 have a chance of having their hits nullified. Chance scales with difficulty.

This challenge can now be played on Deathmatch mode.

Beta v2.2:

Combine units can no longer deal friendly fire to other Combine units.

Beta v2.1:

Adjusted spawn rules to try to prevent Combine squads of ridiculous numbers from spawning.

Beta v2.0:

Overhauled spawn rules.

Added a "temporary damage barrier" to marines against Combine enemies.

Added a damage resistance against Grenade Launchers to Combine enemies.

Beta v1.2:

Increased the chance of Combine squads prespawning.

Beta v1.1:

Adjusted spawn rules to keep Combines from randomly spawning near marines all the time.

Due to the simplicity of the challenge, this addon will skip its Alpha stage.