Great idea! The puzzle aspect of it was fun, but once I'd reached 0 points I could simply stand on the orbs and wait for the loot to appear and pick it up to just nullify it.
As others have pointed out, the execution could be improved upon. Something I struggled with a couple of times in the beginning was when I reached for the door and went a bit too much to the right and fell out of the screen bounds.
Also I personally felt the text explaining the lore was a bit too long. I feel if you made it more interactive/ part of the game, it could really improve upon the setting.
Also one thing I kept thinking while playing was "what level am I on" after the text showing the level disappeared. Perhaps leave that in?
Also one last thing: I think it'd improve the experience if the door didn't only trigger "OnEnter", but also if you're already standing in it when it unlocks.
All in all it was fun to play!