The third eXterminate beta has now been released.
It's not a very huge release, but contains some important changes.

Changes, additions & fixes:

The "too many npc's" problem:

- Updated the zombie map to prevent the player from
walking in the shadows (where the zombies spawn)
- Zombie movement speed, attack speed & damage is now
increased for each map level
- Maximum live npc's allowed is now set to 80

Other:

- Hopefully fixed the "ai disabled" issue in the
zombie map
- Removed reload time for the Auto-Shotgun
- Added magnet to crowbar to make the crowbar come
back to you when thrown away
- Weapon added: Bouncing Ball

Unfortunately no new maps have been added in this release.
The next release will contain a major updated version of the antlion map, and hopefully an additional one.

Thanks for all response!