Very fun game. I liked the arcade style, wish I could continue where I left off but then it wouldn't last very long, so that's fine.
Some things I didn't like was it took me awhile to figure out how to shoot so that wasn't good.
I also didn't understand what the different vials did. I got I needed to collect the blue ones, but the red and green just say "Clean up" and somehow I got bonus lives?
I after my 3rd try, I realized there was more to an intro than just Boomcat sleeping. Maybe that's because (as you commented below) it's on flash and slower, but you should shorten that pause of him being asleep in the beginning, or maybe make the text bigger.
I thought the game was frustrating since there were times I died when I don't think I should have, like I wasn't standing on a red X but I guess he had a paw over it? Hard to tell.