It's a really good concept, I reckon. The movement mechanics felt great, and the concepts of the game were introduced in a fine way. However, the level design of level 2 was a bit off - I lost all of my followers from trees blocking corner-jumps. There didn't seem to be any mechanic to actually keep most of the followers. It would be good to have more opportunities to gather or disperse followers - either a control, or something in-world like a wall. A highlight for the leader beaver (the one that your camera follows) would be good, as would the camera following the group's central mass rather than the leader (when they fall, it can be a bit disconcerting).
I think that it was pretty fun to gather and let die your followers, I think that's a pretty neat concept to focus on. Using your followers like sacrificial lambs and extra lives.