Very hard!
I would make the hitboxes a liiiittle smaller instead of pixel perfect (you can probably restore the amount of difficulty lost to that elsewhere in the design of the game)
I feel the minimum to modulo with score (100 ticks at the moment) for inverting the charges is a bit low (it's like 1.6~sec worst case scenario), I'm saying because I had a rare case where it changed almost instantly 4 times in a row haha
The background scrolling (or even a parallax effect) could be an nice visual improvement!
Nice remix of a classic, with great theme interpretation, addictive indeed! :)