You like cats a lot, huh?
It was a rough piece of work but still an admirable job. The song didn't exactly fit the flash though, you can't just add rainbows everywhere because the song has the word rainbow in the title.
On that note, the rainbow tunnel/cave thing gave me a little head-ache. I'm a little worried that it might cause epileptic seizures or something...
The song could have also been trimmed to fit the length of the flash as well to give it a definite end, so to speak.
Ending was rather sudden.