That's amazing! I would have loved something like this when I was growing up. If you can do that simple games would be no problem, and who doesn't dream of making their own games.
It's absolutely brilliant for kids - and it seems to be avaialble on Linux, so should be runnable on Raspberry Pi - which could be great for the classroom. It's so easy to add new little bits of functionality and see them in action that she never got bored whilst I was showing her the basics - in fact it seems to be her new favourite app at the moment. I can't recommend it highly enough as a first step programming educational tool (the reason I was first looking at it was because my wife's a teacher and was looking at a good app to teach programming to 10 year olds).
It's certainly possible to write very simple games. The tutorial I gave my daughter was a (very clunky) Space Invaders clone, and I'm going to have a go at something a little more advanced tonight - I've got to make sure she doesn't start overtaking me...
The one place it seems to fall down a little is managing multiple identical sprites - I looked at a rather more professional-looking Space Invaders that someone else had written and it looks like they needed a separate sprite with full code behind it for every single alien, although it looks like BYOB may address some of this.
Also, try 'z' and 'p'.