Meh, redrawing every sprite is about as bad as inserting code: finding new space to insert the extra code, hammering a "call" in there to jump to the new code, making sure to keep the stack clean, making sure nothing tries to jump into (old) deleted code (or newly inserted code, for that matter), tweaking pointers... Believe me, when I coded my custom boss and found a bug that involved removing a line of code, I often opted for the insertion of NOP (No OPeration) instructions instead of the pain of going through the entire code again to fix jumps and calls.
Alternatively, every sprite could be scaled to 2x without being redrawn (flat-out stretching them, basically.) Then the code could be written to work solely in 1x mode with double-sized sprites (...all of which would have to have their display rects re-set... THAT'S a pain
Easy as hell and even more tedious - the worse kind of hack job.
)
I'll see if I can try working with double-sized bitmaps this weekend if I can crack the entirety of the rendering code (doing good progress so far!) If so, it'll just be a matter of adding the sprites as they're drawn...