I believe me or someone else might've done this awhile back, but I find it fun to think up games I'd really like to see that haven't been done yet and could make for a fun time.
I got the idea this time watching some slick promo for a likely lame mobile game, but it got me thinking about a zombie game, but with a military force. Not side games with wave based zombies, or solo survival ventures, but like Battlefield World War Z. Large scale maps, destructible terrain, hefty weaponry, multiple zombie types and massive amounts of zombies, it's something I'm surprised was never done when zombies had way more hype going on. Everyone was trying to just latch onto like DayZ, or Call of Duty Zombies, but nothing else outside of the Walking Dead story games, Dead Island/Dying Light, or Left 4 Dead and State of Decay. People complained about the amount of zombie games at a point, but like there aren't a ton of a really good zombie games.
For this, like I said, bigger, more open maps. Modern military weaponry, though limited to some degree, as it could be set abit deeper into the infection cycle, so tanks and heavy vehicles are used sparingly, minimal air support, local communication only. Not only would there be zombies and mutated types, but it would also have roaming gangs trying to get military hardware for themselves or going as far as foreign invasion utilizing the infection as a way to take over, so Red Dawn meets World War Z meets Battlefield lol I think there's a fun game in this with a good story to.