I'm missing 3 gates for the Gate Success! achievement. From reading about it would seem 1 of them is because I opted for Detour but where are the other two? I've every collectable, completed the obstacle course, everything as far as I can tell. Any pointers?

Edit: Just found one I'd missed in the volcano. It was the first gate into the lava ancient frog level, I must've walked straight passed.

Edit #2: I think the volcano one counted for two? I'm now just missing a single gate which would be the one in the tower.

I'll leave this here just in case it helps someone.