Thanks for trying out the game! There's currently no end to the game RN. I did get close earlier today to breaking everything and thought that could be a cool goal to beating the game. I only did about half the map I first planned because I ran out of time so that could be a pretty tough objective at the current skill level with a bigger map.
There's a key that will always drop from one item that's in a bit of a hidden spot if you want a hint... it's located in an item that's near an exterior wall of the building . There's also a 1% chance you get a key randomly from breaking a locker, tree, or lunch table. My original plan was to have keys in the same spot but I only got time for one door. I might do another update to the game and add in some of that stuff.