A FPS or TPS based on the idea of modular loadouts and somewhat futuristic weaponry.
Gun customization is a big part of the game- most weapons have a current weapon as the base of the model, but attachments run the gambit from plausible to phlebotinum-coated. For instance:
Let's say we have a base similar to the AUG A3. It looks like an AUG, feels like an AUG, and shoots like an AUG.
Or does it? You could change around the magazine to any ammo type that will fit- shell-less electromagnetic rounds, maybe?
You can further enhance it with sights- anywhere from the completely-open hologram sight to sights and scopes similar to today's red dot and holographic sights.
Maybe you want a foregrip, and maybe you want an under-barrel weapon. Or maybe you want a spare magazine holder under your barrel.
There's enough attachments to where everyone in a match could use the same gun with three attachments and not have a single repeat- although, weapons can use any attachment even if it's fairly nonsensical. The equivalent of a sniper scope on a shotgun? Why not.
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Modular loadouts- you first choose a Body Type. This gives you base speed, weight tolerance, HP, and ability to move through a combat zone. Light characters can climb objects easier, heavy characters can bring many weapons to a fight.
Afterwards, you individually choose the type of armor for every part of your body- classified as so-
Head,Neck,Upper Torso,Lower Torso,Upper Arm(L/R),Lower Arm(L/R),Hands(L/R),Groin,Upper Legs(L/R),Lower Legs(L/R), and Feet.
Different pieces of armor offer different things- damage reduction vs certain types of damage are common, but extra holsters for equipment and guns is one thing that can be chosen, among others. Weight is somewhat prohibitive at times.
After that, you place weapons. Active, which is what you spawn with out, then any other holster slots.
Then, you choose equipment- different types of grenades, breaching explosives, all the way up to and beyond a quad-rotor scout/assault drone.
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Let's build a sample Light character. You might think some guns are completely out of reach for Light types, and you'd be right- but there's always an option. LMGs are generally the most restricted for Light types, but any other type of gun generally has a fair spread- even sniper rifles. Let's build a class for a Lightweight designed to get somewhere, stay there, and lay down fire, then escape if needed.
Armor-
Head: Tac Glasses
Neck: ---
Upper Torso: ---
Lower Torso: Anti-Ballistic Holster
Upper Arm L: Equipment Holster (Other)
Upper Arm R: ---
Lower Arm L: ---
Lower Arm R: ---
Hand L: ---
Hand R: ---
Groin: Equipment Belt (Grenade x3)
U Leg L: Anti-Ballistic Holster
U Leg R: ---
L Leg L: ---
L Leg R: AAP Vanguard Shield (A leg-mounted shield, sort of like a plate of metal to stop or reduce the power of most rounds)
Feet: Springboard Running Boots
You'll notice I'm lacking a lot of armor, to keep myself super-light. I did take a relatively heavy "shield" on my leg- when crouched, it's the forward leg, giving me a small amount of shielding even when there's no cover. It's not going to be hit often if I'm standing or moving about, and it makes going prone slower and louder.
Weapons/Equipment:
Active: ROC Revolver (Looks similar to a Colt Python),(Given a single change- fires Impactor rounds, which do well against most types of armor. If it hits armor,it does no damage but it knocks the enemy about somewhat, making their aim jerk slightly- if it hits an unarmored location, the effect is much greater and it does slightly more damage than the basic round.)
Holster: Lower Torso: CWP SSR Sniper Rifle (Looks like an AWP, but it's somewhat closer to the Thompson Contender in that it's a single-round break action.),(Given a high-power, nonvariable scope and Electromagnetic Shell-less rounds)
Equipment: Upper Arm: A/S QRD "Peregrine" A scout/assault quad-rotor. This variant is very fast and quiet, but lacks armor. It can fly independently, allowing it to scout for it's user, but with either control-mode engaging a target is ill advised. It's weapon is a weak microwave-based armament that loses effect quickly over range but disorients anything in it's effect radius.
Equipment: Groin/Waist: H.A.Z.E Grenades x3 (Grenades that produce smoke- the smoke messes with electronics- no thermal imaging works, and inside the smoke, electronics flicker and error. Certain weapons won't fire, will jam, or will lose fire rate inside the smoke.
Overall, this is a class built to get somewhere, set up shop, and disengage cleanly. It's well managed- able to set up the drone to scout while sniping, the camera on the drone reporting an image through the glasses. What failings this class have are often self-inflicted- the smoke grenades could disable the drone and the rifle, and the revolver is a slow reload. The shield is the main source of armor- so midway to the target, any surprise engagements are likely to be fatal ones.
Maps are built around the plethora of attachments- bipods can be quickly engaged on any cover of a certain height or while prone, some scopes can see through thin materials, etc.
Multiplayer has "Free", where any class that meets it's own weight requirement is allowed in, "Point Buy", where all items cost a certain amount of points and no one player may exceed a certain amount, "Free Competitive", where some options are brought down or up to be more equal or banned outright, but without point costs, "Competitive", which has a different set of nerfs/boosts/bans than the free version due to the points system, and "Challenge", where random challenges are given out to teams, individual players, and groups of players- they can be accepted or declined, but every player will have 1-3 criteria to meet in that match. Maybe something like "Use a light character","Use this item", and "Get this number of kills total"/"Get this many kills in one life"/"Kill this player X number of times"/etc.