Have you checked out Guild Wars 2? the whole base game (all story and maps up to lvl 80) are free to try; it does have IAP but they're exclusively cosmetics or Quality of Life items that don't give any advantages in PvP or End game PvE instances.

Amazing news! I didn't even know about this lost Shantae game! I ve still got a NDS but i would prefer to have it on Steam, hoping for that PC release :P