awesome job considering you just started using the program.
hmmm improvements, hard to suggest, perhaps feathering the edges of your cut-outs to make them appear smoother, also (if you didnt already ^^) use the pen tool in path mode to cut out images so if you make a mistake you can go back in the paths history =)
If you don't know what the hell im talking about type it in help =)
You've only just started using it..? Wow. Looks pretty darn good to me :)
The writing would be better in 'bubbles' IMO, but that's only 'cause you asked for comments.
Original idea, nicely done, funny. Yep it's good
:)