I'm putting together a list of entities that either don't work at all, or are partially not working in TF2. These are just from personal experience. I haven't tested everything, so I've probably missed a lot. NOT WORKING env_fire env_physimpact func_rotate func_ladder func_useableladder func_ladderendpoint PARTIALLY WORKING env_igniter (you can hear it, and you take damage, no flames are visible) keyframe_rope (will not resize, follow moving entities; no collision; no parent entity support; questionable dx8 support) trigger_push (won't push up or down) SUSPECTED BROKEN env_particlelight env_particlescript env_funnel I didn't bother listing the HalfLife 2 specific entities that won't work in TF2 (like npc_alyx or func_healthcharger). Let me know of any that you know don't work, or any errors on this list.