Looking into it now, I think the only things that give 1% completion rate that are not required to beat the game are the health upgrades (I think there are 3) and the crystal shop purchases (which also I think are 3).
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Hello ! I didn't find it so i started a new game, and finally completed 100% !
I was stuck at 99% too, but this time when i went back, the teleporter which is activated by breaking a block in middle tower was disabled, so i broke it and it worked !
Thanks you for your help, a really nice game despite some bugs ahah ! ^^