This isn't actually going to be a real project like the others. Rather, it's just a concept I sketched on the spot when asked for "a game concept proposal in five minutes". Later I drew the above mock-up. So again, this won't actually be made, it's just an idea I had some fun with.
"In a pre-medieval fantasy setting, you play as a Tribal Spirit who has been given physical form by his worshippers. Your task is to wipe out the major tribes of the small, bizarre world and assert your dominance by eliminating their guardian spirits and ascending from simple spirit to true Godhood.
The game revolves around the village as a central hub, and a large altar which, over the course of the game, will display trophies taken Predator-style from your demigod victims. Between missions, you can perform a select few side tasks to provide for your tribe, which result in small side bonuses. For example, you could hunt to provide more food for your followers or help in their construction. The bottom line is still the missions, however, so all upgrades will affect this in one way or another (higher max HP, greater speed, new attacks and powers, etc).
The missions, each one designed to take out a specific spirit, are unlocked in tiers, and each target within a tier can be fought in any order. Most levels involve you rampaging through a mostly-helpless village and tearing the shit out of things until you finally invoke the full wrath and manifestation of the tribal guardian, and then it's a big boss fight.
Aesthetic is somewhere between Knytt and Shadow of the Colossus, involving bizarre and stylized locales and wildly-varying tribal guardians."
I'd propose it as something like a melee-combat sidescroller. You fight tiers of bosses, unlock new powers and abilities as well as basic stat increases. Each level is a "FUCK SHIT UP" exercise in pure mayhem that ends with a bizarre and atmospheric boss fight. Side missions would basically just be levels with a slightly different goal and no endboss. Gameplay is simple but fast-paced and full of things getting torn up and broken to bits. Boss fights key.
In the end, I envision sort of a... a close-combat Megaman with the setting variety of Knytt and the boss variety of Shadow of the Colossus.
Doing this mockup gave me some insight to the game's actual interface: First of all, the tribal spirits should be smaller in relation to the game screen, or there's not much room for the player to maneuver. They're drawn large here for detail, but in reality the game should zoom out more to allow better versatility, or the player's commands will be limited to "walk, stomp". Obviously this will leave little detail to the people, but since you're a ravaging spirit, they won't matter much to you anyway, especially once you've got some serious powers to deal with them.
Every village could have tribal elders, too, and shaman, who will eventually summon, empower, and otherwise aid the rival spirit.
Lastly, perhaps if you build up a militia you could bring some warriors with you, but they'd be almost useless against the enemy guardian.
It would be little more than a bunch of guys charging left to right and attacking everything they see. Two little pixelly warriors slashing at each other as a massive tribal god rampages violently through their city.
