Not your problem, you have to press them at the same time for it to work, which isn't great. I didn't design the game with diagonal input in mind, i just remembered that i made a game with the same mechanic before and thought i will test if it works here, and it did, so i made two final levels with this mechanic. (It also break early levels, so that's why i didn't make it obvious that you could do that and didn't make it easier to do it)