Zelda/Sheik as Armin Arlert.
Pit as Levi's squad.
Mewtwo as Titan Eren.
WiiFit Trainer as the Female Titan.
Everything is spot-on.
And most importantly, Rockman as Erwin Smith looks boss!
Props to DeviantArt user AmazingArtistYellow for this awesomely done, hand-drawn animated parody/tribute to Super Smash Bros. and Shingeki no Kyojin (aka Attack on Titan).