What about partial usage or merging?
For example, the mario character sprite. Could you draw the left half of the one without his arms, and the right half of the one with arms, so it's just one arm extended?
Can we draw sprites with alpha(transparency)?
Also this is really bugging me. Some of the tiles have a dark blue pixel on the corner, where some are transparent. They should all be transparent for the right bg to come through. Anything we can do about this?
The background for some of the bushes is white which makes them essentially unusable, its grey area with the rules if the white can be made transparent.