Great game, I love the concept with the health bars as platforms. Its even possible to build yourself stairs upwards without using the ground at all for a while by switching around with the four health bars. Thats very cool and it gets pretty tense fast.
I also like that you don't have to get all the logs from every level, especially since you can only carry 2 logs at a time.
The only little problem is the picking up of the health bars. Because the camera is moving when you aren't standing completely still it gets hard to grab the bars sometimes. Would make it more fluid if it was a bit easier to grab them too.
All in all really nice game, well done!