Some missing clipping which results in getting easily out of the map at the end of bm_c4a3a1 and skipping trigger which opens areaportal near the beginning on bm_c4a3b1.
Fences near drop of barrels and sucking water tube are non solid.
Gonarch can still kick you out of the playable area during the first fight by throwing column at you. Also in cave after the fight one web is visible only from 1 side.
