Open world, post-apocalypse, mecha builder.
So, the description is a bit lame. That said, the goal is this. You are a child born after an apocalyptic event. Your parents were part of an order that remains to protect the planet, even though it was left in ruins. You've got a small number of mech suits that can fight, or be purposed into scavenging components. The gameplay itself is going to largely be RNG driven, with rewards offered either by player performance or by assigning competent operators to complete the missions. The goal will be to cross the landmass, and get from one sea to the other, chasing rumors of an elusive super weapon that can stop the invaders.
Mechanically, your target will have the hardest fights and best loot. The distance from said target will determine how bad the loot is, and how easy the enemies are. Gameplay itself will be focused in four areas; intelligence, deployment, unit customization/research/repair, and travel. You start out with a limited amount of places to travel to, and unlock more as you interact with locals and gain intelligence. Deployment occurs in one of two ways. Either AI team members will be assigned missions, or you will build a team and go on them. The surface is defense and attack missions to repel enemies, while scavenging resources. The underground is where you'll do puzzles and explore ruined laboratories to get new blue-prints and resources. This will all be weighed against a ticking clock, where deploying too few resources, incorrect resources, or your own failures will mean the difference between getting stomped or earning new components that mean you'll be the one doing the stomping.
Our actual ticking clock will be a fuel resource. Running the mecha isn't cheap, and they literally no longer make them like they used to. Fuel will be consumed for AI deployments, as well as personal deployments, though it will not be an in-mission resource (to avoid this being a completely neurotic resource management game).
Why replay the game? Well, the choices you make will matter. If you support a town, and slay an invading enemy, they might not need to fire their defenses, and thus share some of their fuel with you. The same goes for intelligence, so the RNG will be framed around a number of basically defined large events. Between you decisions around these events, what you do for each town, and what you manage to get each play through will be different. I imagine someone telling you about getting a buzz-saw arm in mission two that because it had penetrating damage along with slashing damage carried them through to the endgame with almost no opposition. I'd expect someone else to suggest they got an absolute tank that allowed them to be a living battering ram. Another person would say that on a run through a ruined lab they discovered an experimental stealth generator, and armed with a rusty stop-sign sword they carved a swathe through the enemy. I'd then like to hear someone frustrated that all they seem to get is cores, and an AI army is just too expensive...until another person retorts that you can get a commander that halves that cost by doing a special event.
The up-side is that you can never engage in exploration and combat, and play this as a commander. You can pick-up a plasma torch and view this as a mech warrior like battle worthy of Solaris. You can leave the battling to others, and delve through laboratories patrolled by ancient security bots, where the dopamine hits hard when you find a security console to shutdown the turrets on an entire floor and you know that means free access to half a dozen research terminals that could offer you a whole new way to play with something akin to a BFG. No friendly giants need apply.
The down-side is the need for micro, and getting junk. Being curb stomped by an enemy, and getting their weapon only to discover its power draw exceeds your capacity to make is frustrating. Unfortunately that's just the nature of RNG rewards. You will be most capable just before the end of the game...and even then you can still get a reward that isn't useful or requires something to make it work.
Finally, the story. You are aware of the apocalypse only vaguely, as you've been travelling with your parents all your life and it happened well before you were born. During the tutorial you're trapped in the ruins of a laboratory, where you stumble upon an AI. You accidentally break the tube it's floating in, and instead of just an AI you get a face full of nanites that integrate into the neurological link hardware you had to have to pilot a mech. The link suddenly brings the facility back online, and both of your parents are trapped by enormous sentinel security bots. They are hauled into an experimental box, and you are woken up hearing them pounding on a glass wall to try and figure out if you're still alive. Before you can do anything a cascade of energy fills the box, and they disappear. A booming voice in your head says "Quantum link established, travelers confirmed." You pass out again. When you finally wake a new voice inside your head is asking if you are functional. You awaken fully, get a world building drop, and discover the facility is unique in having a mobile carrier platform for mechs that can be your new home base. You consult your new partner, who shows you what to do, and begin the journey with a timer that the facility gives you, requiring that you get to 4 facilities in a certain period of time to prevent the bridge from collapsing. These 4 are nearby, and act as a tutorial. If you make all four you discover that they could have been stabilized from the original facility (a short cut for new games, to skip the tutorial). You're then subject to resource management to cover the rest of the land mass. As you hit certain locations you'll gather specific intelligence, and if you get 50/75/100% you'll get different endings.
The 100% ending has you use the quantum link to send your now complete AI pal to the invader's homeworld, and absolutely wreck their crap. The lowest tier has you losing your parents and fighting the invaders for the rest of your life, ignorant of being so close to the solution...but at least not alone now you've got a friend. I'd suggest there have been several games that were kind of similar to this...but the ability to do both combat missions and stealth/puzzle missions...or neither...is what would make things a bit different. The balance would necessarily have to be to the easier side...so less FTL and more Death Stranding. Likewise the mechs being built out of spare parts is quasi-The Surge, but instead of duct taped junk you're looking more at a version of Armored Core without the need to have balance...and thus having stuff you will scrap out or never build.
