After doing something, something that I didn't exactly catch on, I always hear constant strider sounds, exactly on this map. Is that a bug, or some secret feature?

there shouldnt be anything in the map that makes strider (or any npc sounds), my best guess is it could either be lag messing up the sounds (in which case try typing snd_restart in console), or it could be some addon overriding something

if its any help, the map was tested with hl2, ep1 & ep2, cs:s and portal 1 mounted all together

btw the doors in the house get stuck alot and break. especially the ones adjacent to the front door, and the closet doors.

props bounding boxes are aligned with the world, not the house, so if you have a prop against the wall its bounding box will go through the wall and interfere with any adjacent door

doors will also get stuck if its inside another door, which may occur in the small bedroom and its closet

i havent figured out a way to fix it aside from just not having props in the house or having the house be not at a 45 degree angle sadly

you might also try using no collide on props and the door
or maybe even the door itself

I pulled the props away from the wall as my first guess, but the problem still persisted. I think the wall geometry is too close to the door a well.

doors dont care about walls, just props iirc
ill have to mess around with it later, for now you can use the physgun to rotate the doors manually