User blog comment:Solowing106/Canyons/@comment-1824272-20120805020209

The hardest canyons here have got to be Greased Lightning AND One Night Stand. The Ace Combat 2/3DS canyons, definitely the hardest. They're very lengthy but so very tiny to navigate through.

Depending on your mode of difficulty, Avalon in ACZ could be a cakewalk (Very Easy) or a descent into hell (Ace). Your choice.

From what I've seen, because of its handling, the 747 canyon flight in X2 is also pretty much a descent into hell. XD

Escaping from Stonehenge in Ace Combat 04 could be difficult if you're not paying attention or you go at supersonic speeds. I've only crashed in there because of those two reasons; otherwise it's not a difficult canyon. The same could be said for Ace Combat 5's Payavlenie Ravine, but that's even wider tbh. And El Dorado shouldn't even be thought of as difficult because that canyon is freaking huge. XD