How does it look? I’m working on adding more comments for an easy understanding, but does it look clean? Efficient? Good at all? It seems to run fine, but I haven’t had time to profile. It uses nightly, but only for the mixed_integer_ops_unsigned_sub feature, which somehow hasn’t been stabilized yet. 
I’m not too sure about the UI, readability of the grid, tiles, and everything. Feedback is appreciated! Thanks!