The visual and audio presentation here is great. All the essential ingredients are here.
Gameplay-wise it's simple and linear but it plays really well. There are really only a handful of places to go, once you've explored things, and as a scaled down Metroidvania it's pretty obvious where to go when you pick up a new item. The platforming is generally pretty easy and this is probably the biggest gameplay issue.
I think my biggest frustration with the game is having to restart after every ending. I only got the Devastating ending and having to redo everything for a new ending is a real pain. You could circumvent this either by allowing save files, or by having a checkpoint you can go back to before making story-relevant decisions.