This sucks on ice
I know it's a short but making it 22 seconds long makes the whole fight seem pointless, there's no tension, music or anything that makes a good animation. The plot is unclear as Chara simply walks into a room and then gets blasted out later to be killed by Gaster (and no one knows why). Adding some music, a storyline and extending the fight could make the animation better.
Could be a bit longer, but the animation is pretty smooth!