The Giant Slayer

The Giant Slayer is a game where the goal is to kill a single enemy -- a massive giant, far bigger and stronger than the player. The game world would be the giant's body (perhaps with some play outside the giant, collecting the artifacts or tools). The player would scale the giant, completing various objectives to damage or weaken the giant (destroying 'hearts', damaging or weakening parts of the giant, poisoning it, etc), all towards the ultimate objective of killing the giant. Some Metroidvania style gating could be used as well. Due to the fact that the game takes place on a giant, the overall world structure and certain mechanics could change based on the Giant's behavior.

Important Design Consideration

An important question, however, is how to make the game feel cohesive and like an actual giant-slaying battle, rather than just simply a set of levels that happen to be in/on a giant. Tying interaction with the giant itself, rather than just with environments that are 'part of the giant' (ie "I'm in the giant's stomach now, which is just an area itself" would help a lot, but how can this be done?