I'm not as mad as the OP about this but it IS kinda weird that this jam rewards entries that break the rules. Obviously not respecting the sprite limitations means you can draw nicer sprites. I went back through previous jams and p much all of the winning entries used sprites at whatever sizes they wanted, didn't keep to the grid, used all 4 colors for every sprite etc.
And the response to that is generally "the official rules are only that you should make a game with 4 colors and it should have a 160x144 resolution" but why are we calling it GBJam then? At that point it's the Four Color Small Screen Jam. #FCSSJAM2017
I mean it's just a game jam so it's fun regardless, but it is a lil' odd!