I'm up to Wolverine's flashback of the Weapon X facility, which I think is optional though highly recommended. It comes just before the Power Plant mission.

The first Morlock tunnel wasn't as bad as I remember it. It was actually kind of fun.

I found a sketch I didn't get in my last playthrough. It's a drawing of Rogue and Gambit.

I also forgot to mention how I also hated Emma Frost even though she was involved in some funny dialogue with Toad.