Even though it is still in development, Forest of the Blue Skin is a high watermark among HTroidvanias. Why?
Well, solid pixel art (And all CGs animated, collected upon capture or finding alt animation tablets) is a good start, and Zell pushes RPG Maker outside of its comfort zone quite well (To the point where they have now had to move to a later version of that tool due to engine limitations.) Now add in multiple areas being unlocked by abilities, capturing monstergirls to be a small puzzle in and of itself, the ability to unlock animations without being defeated, and a solid community translation of the UI the developer has encouraged (The game has little to no dialogue, but animations are expressive)... And you have an overall solid model.
Well, solid pixel art (And all CGs animated, collected upon capture or finding alt animation tablets) is a good start, and Zell pushes RPG Maker outside of its comfort zone quite well (To the point where they have now had to move to a later version of that tool due to engine limitations.) Now add in multiple areas being unlocked by abilities, capturing monstergirls to be a small puzzle in and of itself, the ability to unlock animations without being defeated, and a solid community translation of the UI the developer has encouraged (The game has little to no dialogue, but animations are expressive)... And you have an overall solid model.