In the first part of The Burrow, where you climb up the tree, there are almost no available interactions. You can only move the camera to look around you while you go up.
In the second part, after you go into a weird hole at the top of the tree, you reach outer space and can finally start moving. In this part of the game you can travel from one asteroid to the other, although you never know exactly what for.
After exploring for a long time, you'll notice that some asteroids have more holes and butterflies that disappear if you get too close. If you manage to catch one, you'll get a little surprise.
The Burrow is a rather strange interactive experience that's not exactly fun, but can be quite stimulating. And the graphics are excellent.