npcs don't move

all of the zombies move but none of the combine walk - they just stand there holding the guns

Uhm, what map you tried?

Try to see if you have ‘Ignore Players’ checked from the bottom of the NPC menu.

It doesn’t work in flatgrass because there isn’t any nodes.

gm_construct and i have ignore player off and the ai isnt disabled

It might be from the guns. Try making Metrocops with batons/pistols.