For those who like the pixelated artwork: there is a lot to gaze at. Despite this look not being my cup of tea I don't consider it an ugly game. Suddenly seeing a giant skeleton being part of the landscape is indeed quite remarkable though other games do it better. The selling point that you will enjoy exploration falls flat. Moving around itself can pose problems for example since it really isn't always clear where an edge ends and which distance you can 'warp' to leading to many unnecessary falls and loss of health.
Two major problem are the very vague story build-up and the gameplay. The game tries to tell the story through confusing cutscenes that don't really clarify the immediate goals much. Soon it becomes clear you have to collect some kind of shards to unlock the great secret but I never felt motivated to progress. On the side of gameplay the controls aren't very responsive. At points the number of enemies on the screens is just too much and feels plainly unfair. Yes, your skill-level will rise after a while but unless other hard video games I didn't experience a feeling of satisfaction when I finally cleared that room just to be rewarded by another small cube.
Another issue that annoyed me were the autosave points. The placement is fine but you are always stuck with the health you had when you activated it. Since healing opportunities are rather sparse you get stuck with that health even if the next room is full of enemies with no extr health in sight. Meaning plenty of backtracking just to get a decent amount of health to tackle an unrewarding challenge.
Therefore I regret to say that I simply stopped playing after 12 or so hours of gameplay. I just couldn't muster the strength to continue the game. The vague story will have to resolve itself.