I don't want to repeat what others already stated (it's fun and engaging), so I'll skip that.
My only suggestion so far is the control scheme. I feel like the default one should be Left/Right to Move Left/Move Right and Up/Down to rotate, so I changed it. However, this does not change the Up/Down keys having inconsistent behaviour. I would expect "Up" to make the bearcycle to rotate nose-down and "Down" to rotate nose-up (or viceversa) independently of the facing of the bear.
It's looking very good and I look forward to trying future versions!