Thanks for playing! Most of this is being addressed in 0.9. Been doing a lot of work on placement. Also yeah, the sneakers is a bit of a meme right now, due to my terrible balancing people end up with hundreds of them lol. Will certainly be fixing this too.
I do wanna clear up that the night flyer wont spawn in the air, it always spawns on the ground and flies up. That enemy specifically will only spawn on grass or dungeon bricks, so the inside of your house should be protected as long as the floor isn’t made from those materials. Placing torches will also prevent them from spawning on the surface. They need a red light level of 0 to spawn.
That being said there is a bug currently where if a lot of enemies group up outside of your house, sometimes they can push one of these guys through a wall.
Could you post a picture of where they spawn for you so I could see what might be going wrong? If it’s a bug I’d like to make sure I can fix it.