The animatic at the moment feels like it would be very sound-effect heavy as opposed to a running soundtrack - at the moment anyway. My suggestion would be to get the sound effects in first and then think about the music!
Sam! This made me laugh - very nice, and Tom's absolutely right - you don't need 'solid music' in this - it would be too much like applying a layer of gloop over the top; your sound effects should resonate from the characters, interactions and impacts etc. I forgot to show you these examples - just for reference:http://vimeo.com/23806273http://www.youtube.com/watch?v=GCJ0CZ_Lwfc (this one is particularly good for sound!)I also really like the hand-drawn annotation - I'm sure it is already your intention to keep this quality, but it lends your film informality and comedy.So - get some SFX going on in here - it's a big job, so get stuck in :)Onwards!