Well, how many photos with different angles can a person take of these? Not many I imagine. What you had to work with did good. The black and white is good. Maybe putting a 'buddy' inside, letting him or her...sit inside or lay down and have a huge smile on their face...might be cute, and give it a bit of character. But as it is...I think maybe it needs a bit of something to give it some "oomph" eh? Don't give up...try something else and see what it looks like...
I'm sure the black and white helps this shot. I have to agree with Verena though, a third element in this pic would have helped bring the subject to a different level.