Just letting you know in case someone hasn't figured it out. But some windows (when completely opened) you can jump crouch through and get outside the map.

when a buddy and I tried playing this it didn't have the "Start Game" button like i saw on others players games on youtube

Also i've noticed a bug with the boss at round 15 where he'll get stuck running into the wall and seems impossible to kill until you can manage to un-bug him. Not 100% sure but i think it may have been something from the gravity spikes

Anyone else have an issue where the little purple skulls disapear and you can only see them at random times? really annoying cause i just got the map and trying to find the easter egg out by myself without tutorial. If i missed somewhere where it's a known issue lemme know. Thanks

Super fun map and very challenging. HOWEVER, there is a huge game breaking bug where you can literally jump over/around each one of the barriers without purchasing them all the way up to the top. Not only that, but after you climb up so high and kill all the zombies the rounds start to skip. So i got to round 40 just now in like 15 mins. Only thing you have to kill is the spaceguy and the fire zombie cause those put a pause on the round skip bug.