Like Diablo or roguelike games. Maps are made of at most 10 blocks of 50x50 cells. Each block can have up to 4 gates, eg a North gate is a hole from 24,0 to 25,0, and the rest of row 0 are walls. Each block must have at least one gate. Blocks can be hand-made or generated. There must be exactly 3 blocks between the Start and Finish blocks.
Check: Adventures in Level Design from Joris Dormans, PCG workshop from FDG, and Automatic Generation of Dungeons for Computer Games from David Adams.