* levels 9, 13, 15 and 36 have gravity
* levels 15 and 17 are impossible when not playing together
* levels 26 and 34 can be played either alone or together
* levels 18-25, 27-33 and 35-43 should be played AGAINST each other, he who kills all the others first wins (although not formally).
* levels 17 and 26 are not finished
