Compared to the original Castlevania, Simon's quest is much more open-ended (hence why this series is known for pioneering the "Metroidvania" genre). This is derived from the objective: instead of simply marching straight into Dracula's hall, in this game, you have to collect five parts of him in order to free yourself (Simon Belmont) of his curse and defeat him once and for all. The more open-ended nature of this is core to the gameplay, with weapons that were previously power-ups now being permanent upgrades, currency acquired from enemies that can be used to purchase these upgrades in towns, which are also a new addition. There is one slight snag: this game can be obtuse about what it wants. Within the game itself, the story is not presented at all, and the villagers, along with all of the other objects in the game, provide very little direction. This game would have benefitted greatly from a simple map, and if you were to play it today, I would recommend finding some sort of guide, unless you feel like really roughing it.