Which part are you referring to? I made all of this without hacks.
To activate the last chamber you move a sprite (maybe a plug) to a corner, then the chamber change to active (i can enter).
How you can change sprite states in the same room?
Sorry my english.
The battery that you move is actually a non-wall tile which is on top of a teleport to another identical room where the tile has been moved. It requires many many rooms and many duplicates of NPCs. It is time consuming but the result is a bit more interactive than what is typically seen in Bitsy.