Very cute little one! Sadly not a lot to comment about it tho x)
The art is pretty simple but sweet and everything feels very fairly polished, and every death to fire does feel very painfull, wich is a good thing, in this case xD
It also felt pretty bad to burn down the forest honestly... despite the simplicity of the graphics you really nailed down the feeling of how dangerous fire can be.
The gameplay is pretty funni, I like the idea of having to manipulate the enemies movement in order to defeat them or solve puzzles, it's a very creative way to make a non-combat game.
However I... Didn't actually need to use the Goblins for puzzles, thought x)
If you just hold the key in the direction of the wall the little prince will just squeeze throught the gaps and stretch his hands to reach whatever is on the other side. Of course he can't really fit fully so he will never manage to actually get to the other side, but all he needs is to grab the key and move on, anyway.
This is also not really a metroidvania honestly. Of course it's very short, but other than that it also don't have any actual character upgrades, only two keys (You don't use the candlestick for anything but opening another passage, wich is still just a key, not an upgrade)