This is a difficult one, I really like the concept but the gameplay makes it difficult to play though there's something alright.
if you decide to continue on this concept, I'd suggest first having the player only use 1 number, all enemies stay with a specific number. That way you explain the good/bad combo, Then introduce changing between 2 numbers in the next level, that eases in the idea of changing your own power. Adding features like that will make the gameplay a lot more accessible I think.
I did see some slowdowns in the game, might be my browser having issues.