Before Skullgirls, that is.
With a fight stick in my lap, I checked out the mix-ups tutorial first. Here, the computer tries to catch you off guard with a bunch of mix-up combos. But the beauty of this is that there isn't any set pattern in place, so the CPU never gets locked into stagnant combos. It's fresh during each attack pattern and it really kept me on my toes.
I was surprised, since a majority of the tutorials in fighting games focus on being offensive and attacking nonstop -- hit confirmations and punishing exercises will certainly be included here -- but skilled players will tell you that constantly attacking is about the dumbest thing you can do. Spacing and a good defense are as paramount to victory as punching your opponent more times than they've punched you. And that's why I was completely enamored by Skullgirls' tutorial area.