The new mutator is VERY cool, but the biggest issue with it other than crashing is that there is no significant cooldown window for enemies when they spawn in. This has been an issue with the normal game, as I’m sure many of us have seen playing twitch mode or even the normal game on rare occasions when an enemy spawns and attacks within half a second. This issue is compounded with Tzeenchian Twins because the number of enemies spawning in right in front of you is obviously huge. The net effect is that you have enemies spawning in and immediately attacking you before you even finish your attack animation.
Even just a half second longer delay on being able to attack when spawning in would help this issue. Considering that enemies are not supposed to spawn right next to you in the normal game, I don’t think this could lead to exploitation.