Fun entry! Here are my complete feedback:
* Positive points
- The concept is very interesting, it reminds me of Worms or Lemmings, because of the "sacrifice" feature which allows to progress/win like in these games
- The graphics are pretty simple, but simple and lively
- Good sound feedback
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* Negative points
- The skull is a bit slow, which made fail some jumps because I anticipated too quickly
=> Overall great work!