GP:
Metroidvanias, when done right, simply seem to have an edge in terms of hitting the right sensory spots in the brain when it comes to exploration. No amount of grindable (or in modern terms, PURCHASABLE) abilities can replace the satisfaction of finding a new ability and being able to apply it to previously unexplorable segments of a game. Julian Laufer, the sole developer of Outbuddies, has achieved something just as satisfying as the classics in the genre. According to the in-game statistics screen, I have explored 57% of the map in around 7 hours and died 102 times (shameful, I know) which is why this is more of a review in progress.
Source: N4G PC Outbuddies: Review In Progress- MetroidMania