Alriiiiight I see !! Thank you so much for this ! You seem to end the game with 16 crystals. Which is enough to buy any perk. (first perk costs 10)
One is orange as soon as you open "The heart". So you actually DID buy a perk. But it did it immediately, and the game did not understand you bought it. You seem to play with a controller, maybe it's a controller issue. We are going to resolve that because yeah... That's hard, after that you're stuck forever. Kind of a big one there !!