About the 18x18 preset
This is a starting point for the custom game builder: a medium 18×18 board carrying 50 mines across 324 cells, or 15.4% density. That puts it in the same difficulty band as Intermediate (40 mines on 16×16), so what changes here is scale rather than difficulty — 274 cells to clear instead of 216.
Tips for This Size
This medium grid balances challenge and play time. Focus on clearing large areas first.