
Some games don't really need to operate on that grid format, and making it so that it's only possible to have pieces exist on one of the squares, or a few of them, is incredibly limiting in some regards. I'd say you definitely need to make auto-snapping to the grid an option, but maybe an option where pieces don't do that would be good too? Also, it'd make changing things' sizes easier too. If a piece is a bit longer than it is wide, then your only option now is to make it twice as long as it is wide, and not everything that's a bit longer than it is wide is twice as long as it is wide.