It is! :3 My all-time favorite puzzler. I should spend some quality time with it today.
Everyone says square gates are best for fighters, because you're not supposed to push the stick all the way to the gate so the square gate gives you the most freedom. I play more than fighters with it, so I opted for the octagonal gate. It was kind of a bitch to get the square gate off but it was worth it I think.
I kinda wish there was something halfway between a circle gate and a rhombus, where you could hit the diagonals but there are only "hard" corners for up/down/left/right.