Literally if we don't include the TAG4 maps, and regardless of when/how many players FC'ed it, 4d is the hardest in my opinion. Cookiezi was the only person to FC it without a difficulty reduction mod, where else everyone else below him who FCed mostly used a Half Time mod.
You can't deny the fact that it is so stamina draining.
You can't deny the fact that it is so stamina draining.