I've been looking forward to this (when I'm tuned into SRB2) since the WIP thread, and the full release is excellent. The animations here do a lot with a little, especially when Sophia gets up to speed and really starts zooming around, she feels heavy and nimble at the same time. The spike-breaking and wall breaking really do a lot to help sell her as this bowling ball with a rocket strapped to her. The shooting is excellent too, especially on stages like the Tails and Eggman stages of SA2Blast with a lot of enemies, it's very satisfying to rapid fire demolish everything in sight.
And again, the shades are awesome.
(Wish the climbing sprites were better, though.)