Hard, but fun.
In the game, you play as an angel called Pit who fights lots of monsters using his bow. Despite being an angel, Pit cannot fly until you obtain the ability to do so. The levels have some exploration factor, and you'll sometimes struggle to find the exit.
Fortunately, the game has a save feature, because you'll probably be dying a lot, because the difficulty is high.
At the end of a series of levels, you get to fight a boss. It usually took me multiple deaths to understand the boss's pattern, which adds challenge, but also makes it tedious, because loosing to a boss takes you back to the beginning of a level.
There are multiple power ups you can obtain by doing certain tasks, and you better do obtain them, or otherwise, the game will end up really hard (like it did for me...) so even though a guide is not required, good exploration at least it.
9/10
Presentation: The game has good graphics and the music is decent, but gets annoying quite fast (some of it).
8/10
Replay Value: The game has some replay value, since there are many power ups and other stuff to obtain and the levels have multliple routes, so it will last for a while despite its appearance. The difficulty also helps in this matter: you'll probably be replaying levels a lot.
9/10
Fun: I didn't have quite as much fun as one would expect. The initial levels felt good, but the later ones make the game a chore, plus if you don't get the power ups, you'll be stuck for a while, which is never nice.
6/10
Overall: A good game, that offers good challenge, but it may not be for everyone. Check it out if you have a chance and are up for a challenge.