Well known but often overlooked, the original Adventure Island could be considered a pioneer of the side-scrolling platform game. Although it wasn't quite the leader as was Super Mario Bros., it was at the front of the enormous pack that followed behind. Released only a year after Mario's first venture into the Mushroom Kingdom, the game introduced a fairly unique concept: sustenance. As Master Higgins avoided enemies and traversed pits, his life meter would slowly drain. In order to stay alive, he had to collect fruit along the way. This distinguished the gameplay from Super Mario Bros. in that the focus was shifted more to "get out of the stage as soon as you can." One could argue that this led to speed-based platformers such as Sonic the Hedgehog.
Not content to rest on their laurels, Hudson's Adventure Island spawned many unique sequels. These included additions such as the ability to ride dinosaurs, an incredibly helpful inventory and item storing system, and even Metroidvania inspired gameplay. Certainly, Super Adventure Island II has deeply satisfying adventure-based gameplay, similar to the Wonder Boy series (which isn't surprising, considering their relationship). Let's hope Master Higgins stays true to his word. And if so, it'd be nice if Hudson Soft included another unique enhancement to the gameplay much in the way that previous sequels did.