>>720438779
Me. The art direction (not "art style") made those games interesting. That's only part of a game's appeal, but it certainly fucking helps when all you see at first is a trailer or someone else playing it.
A philosophy I abide by is that enemies and hazards should be introduced separately, at any point and for any length of time, no matter how brief, before putting them together. Especially for platformers and action games, it's nice to feel like the level is building up to something. Levels don't feel as fun to play when the difficulty curve feels flat throughout, even if the difficulty to start with is high. Sequences that are more elaborate with enemies and gimmicks and hazards need to be set up with earlier sequences.
I also think that "metroidvanias" need to move on from leveling, the need for currency, and skill trees of any kind. Let the player find items that grant those increased abilities and powers, it's always more satisfying than grinding for them, even if grinding is minimal.