Demon's Crest springs to mind. It's a G'nG spinoff but it played more like Megaman due to new abilities gained as you progress. Some of which enable access to new areas/ secrets. I always thought of it as a move towards more open world action platformer games coz of the overworld map and town.Same with not doing a crossover with another action platformer such as Ghouls 'n Ghosts.
