My friend had a similar issue, and said that it was being flagged as a pop-up and getting obliterated, maybe try and turn off whatever anti popup stuff you got? Not really sure honestly, thought I'd mention it.

If you still can't get it to work, just vote it all 0/1 stars. Me and the poster really don't care about the outcome at all. Mostly did this to experience making something in 3D Unity which we hadn't done yet.

There is a horribly edited win screen at the end of the level, crouching reduces detection range.