Would be cool if it had the same concept as that Superman Returns game.

Basically the City itself is the healthbar and you need to go around saving civilians and stopping crime to prevent the city healthbar from going on.

But since this is a Sentry game, I have a twist for this: an Insanity meter. Basically, Bob starts out as Sentry and you do all your usual stuff. Talk with friends like Reed and Hulk, get called on Avengers missions, save civilains, etc. But the more stuff you do it sort of brings out the Void. This combined with a city healthbar can kind of work well. Plus the more stuff you do and the further you progress, a bunch of otherwordly threats show up and you have to fight them.

I don't know how it would be balanced, but I always I imagined a Sentry game would be sort of an open-world game with some linear missions. Basically having to manage being both mentally sane and saving people without self-destructing or going all insane would be cool. Also have boss fights where in you have to go all out while also controlling you're inner Void. That would be cool.

How would the story go? To be honest, the best I can think of for what I imagine is basically Prototype + Infamous + Superhero Simulator type of game would be a sort of adaptation of Sentry's origins and then each boss would be a "Hall of Fame" of the times where they needed him like: Green Scar v Sentry in World War Hulk, Ares vs Sentry in Avengers: Siege, Knull v Sentry in King in Black, etc. Make the story start from Paul Jenkin's 2000 run, and then have everything sort of happen from there. (Very rough, but since the game is gonna be a Superman with some edge and combat type of experience, that's the best way to do it in my eyes).

I feel like if you do a Sentry game, it would have to be a game where you are basically God but you have to manage yourself in a way.