The expert minesweeper game has a playfield of 16 x 30 blocks, with 99 mines, for, on average, 4.84 squares/bomb.
The maximum custom playfield is 24 x 30, and you can add potentially add more bombs than you could possibly clear. Even if you "only" had enough bombs for their to be about as many squares per bomb as in expert mode (about 149 mines), it should be harder than expert mode, because the larger size would mean there's a higher chance of ambiguous mine placements (meaning that the clues aren't enough to solve the positioning; you need to guess) appearing.
But, anyway, the challenge is, what's the maximum number of bombs you can put on the largest custom playfield and still beat it? Time isn't such an issue; just the number of mines.
I'll start by putting the bar low, at 160 mines, or 4.5 squares/mine:
The maximum custom playfield is 24 x 30, and you can add potentially add more bombs than you could possibly clear. Even if you "only" had enough bombs for their to be about as many squares per bomb as in expert mode (about 149 mines), it should be harder than expert mode, because the larger size would mean there's a higher chance of ambiguous mine placements (meaning that the clues aren't enough to solve the positioning; you need to guess) appearing.
But, anyway, the challenge is, what's the maximum number of bombs you can put on the largest custom playfield and still beat it? Time isn't such an issue; just the number of mines.
I'll start by putting the bar low, at 160 mines, or 4.5 squares/mine:
Crawl and 1000 
