It's too long/slow. There are entire animations that aren't that long.
Also, it's just an intro. It's an intro with no animation or story with it. I know you said that in your comments, but that still doesn't change the fact that it's a beginning without a middle or end. It's an intro to nothing, and that makes it a pointless part or bit of a finished product.
Please don't submit things that aren't finished. This isn't Introgrounds. What you have seems to indicate that you have something cool in the works, so we look forward to seeing it. This isn't finished, though. Please don't submit parts of things. Please finish and submit. :)