Hey so this is a bit weird, but after talking to @GrizzleMarine and getting ideas, I just decided why not? This is my concept for a blend of the 4v1 of Evolve, and the story driven co-op design of Left 4 Dead. So without further ado, he’s a rough concept for a 4v1 game.
During the mid 80s (can be changed to any time period really, I just like the idea of setting it in the Cold War, post Vietnam War) governments around the world find crashed pods without a trace to any known Earth-based launches. Shorty afterwards, containment and research begins, but more start to come. Eventually the pods start to activate, releasing spore like structures that infect and mutate living organisms. Due to the sheer amount of pods, these organisms start to spread, infecting and multiplying. Due to the limited technology, and the fact that the organisms would almost always kill (or the governments would capture the individuals) before they escape, the aliens are mostly unknown to the public. The governments of the world rush to stock up on nuclear arms, but secretly establish a multi-nation armed force to combat the alien threat.
Tl;Dr, alien pods start raining down on Earth, the volume of which leads to outbreaks that mutate organisms. Governments form task force to fight it.
The game is, like Evolve, split into two ways to play. There are the operatives (working name), or the humans, that are given objectives to complete. Usually these would bet set up either in open ended decisions for the players to choose, or would be multiple stages of a level that have different objectives unlocked after the completion of an objective. The humans must either complete all the objectives, or kill the alien player to win the match. The humans would be first person, and be separated into classes. The current classes are Bodyguards (damage and area denial), Hunters (CC and tracking), Engineers (buffs and debuffs), and Medics (Healing and Slowing of Death). A traditional layout, but one that works and allows for room to have characters with kits that are all their own.
The alien however play out differently. The alien player has their own goals they need to achieve, but those goals usually take longer than the humans and will lose if they only focus on them. The alien player gains power through causing damage, some power through wildlife but a lot more through damaging the humans. This power allows the alien to increase its strength by upgrading its abilities (and maybe health/armor?) by using branching ability trees. Upgrade an ability that makes one player not able to see you to an ability that creates an AoE that causes players an AI to not see you. This allows for players to choose how they play an alien, and gives more options for how an alien is designed. Turn the low health trickster into either the silent stealth assassin, a quick glass cannon, or a disorienting trickster.
One big thing is that the game features AI enemies for the humans to fight, and AI wildlife for the aliens to use as power up sources. For the humans, their enemies are the mutated humans that the aliens create. These are essentially zombies, with different types of enemies being used and some tools used to prevent them from being a typical large swarm of mindless AI. These AI would be like, coordinated piranhas that are always wanting to infect organisms. The alien player has some control over where they want the AI to be (with some aliens having more control than others), but in general the AI will choose to stay closer to objectives or ambush players where their type of enemy is most effective. For the alien’s wildlife, they are much like what Evolve had. Some always run away, other will put up a fight. These are mostly just for the alien, but the humans do stand to gain by killing the wildlife, since the alien only gains power through dealing damage.
Something I wanted to go for was with the aliens, taking inspiration from aquatic life. One playable alien could be like a reef, basing its abilities about dealing AoE attacks and summoning swarms of AI to overwhelm the humans. Another would be very squid/octopus like, floating in the air with tentacles trailing, using mind related attacks and manipulating the humans directly.
With the humans, I would go from beginner level operators being grounded and using equipment from the time period, and then progressively getting more sci-fi (taking inspiration from 80s and modern stuff) with the operators, blending alien technology and human togeather. An entire tier of hunters based around knowledge of how to counter the aliens, then th tier above them starts to adopt alien technology.
Something to keep is the dark theme that L4D and Evolve had, with some humor thrown in. To these people it is very serious, and they take the work seriously. Throwing in some dark imagery (say dead bodies or an entire town that was taken over by the aliens) would help set a mood, but keeping the humans likable will be an important part of keeping players in the game.
We have to learn from the mistakes from games that come before us. People didn’t like how Evolve handled DLC and Microtransactions, so we use what they do like that also makes us money. L4D2 wasn’t received as well as its predecessor, so we see what was different and better in either title, and we apply it. With some work this idea could fail or succeed, but its better than not trying.
Now, time to enjoy some quiet time before questions or ideas come up.