Keep practicing
Personally I don't think it's a good thing to have credits that are longer than your actual video. The good thing is that you do know how to animate sprites to an effective level, but you need to work on story writing and in this case time length. The punch line just wasn't anything to really laugh about and it all happens rather quickly. Just keep practicing and you should nail it, after all I see that this was experimental so just here to offer some advice.