I don't want to spoil to much but.. you need to push each side up then the middle to the side. As for the heart, it's not needed to finish the game. You still have an other section to do that'll have more torches :)
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oh! I'm stupid, thanks. I made it to the end, got that box puzzle done for the heart, etc. :D ok finished it but I died a few times so I'm a ghost :D
still unsure if the floor 1 entry can be accessed :D and for anyone wondering, I think max hearts is 8 (and max level is 17 maybe, it just says "max level" then)