I have managed to get around multiple door buys and get on top of many buildings, and I have been outside of the map many time without the need of cheats. Constructive criticism, add more barriers around the map... A LOT more. I have been looking for 2 hours and have gotten to the end of the map without buying ANY doors. I have managed to get on top of several different tall buildings due to pixel walking. So my advice, add more barriers.