Ah yes, the locker... lol. I'm really happy someone noticed that secret. You won't get the combination by beating the game - you have to find it somewhere in the environment. To save you some time I hit it somewhere in one of my rooms. It's a 3-digit numerical password. Good luck if you come back and try to find it.
The not knowing where the enemy was was definitely an issue when I was playtesting the game. I tried solving it by adding the cameras, but I agree it could use a bit more work.
I'm glad you like the visuals! I'm super happy with how everything turned out, especially the shaders. Thanks so much for playing! Really glad you had fun!