So I've been poking around with this swarm-sdk-template[code.google.com] project, with npc_antlion grafted into the mix as a proof-of-concept (on source 2007 atm but eyeing perf improvements, as well as stuff like biohazard's deferred lighting) unit. I've seemingly gotten the important stuff working (model, materials, sounds, hates player, runs around, attacks me) except in two respects:

• Attacks inflict no damage whatsoever, and the associated view punch is also missing. My first guess is that the code is directing those effects at the wrong given player entity (I lifted it wholesale from HL2 2007), though also possible is that somewhere along the line I messed up animation events or something (though the attack anims play just fine). Also possible I suppose is that the damage/viewpunch aren't being felt at the client level? Could use some suggestions as to adjustments.
  
• Doesn't appear to use the navigation meshes (unsure if this is simply the NPC needing to be set up for use of such [being that it originally used a node graph in the hl2 games], or the nav mesh needing special flags for such)

Naturally the first problem is far more game-breaking at this point, but the second is also something I'd like to address one way or another down the line.