I am trying to write the story for a game. It starts off well, only to end up really being horror. The goal is supposed to slowly become like that, but without the player figuring it out until it is too late. The type of plot is man vs. environment during a zombie outbreak, and my goal is to slowly introduce the terror to the player, ending with the completion of said outbreak. What are ways I could subtly hint and foreshadow, without giving it away immediately?
I'll suggest a frame challenge to this question.
Many questions here are something like:
"How do I fool my readers…"
My opinion: this is not a good way to approach a story, or readers.
Did you ever go to a restaurant, order a spinach salad, and after waiting 30 minutes they bring you horse meat?
Did you ever pay to see an MCU movie, then after an hour you realize they are showing a romance about a lonely woman on the moors?
You speak to management. You point to the menu/movie poster that is clearly labeled as something else, the thing you paid for. Manager says it's no mistake, they just lied to you.
That 'other dinner', that 'other movie', would need to be f___ing amazing to overcome the hostility and annoyance felt by everyone (and it is everyone) who was swindled.
Bait-and-switch is not a good marketing tactic for stories.
Genre IS marketing. It is labeling your 'product' with the ingredients – not the exact flavor, but shoppers know the basic components of what they are buying. It's literally what labels are for.
Authors have a lot of latitude within genre to tell the story their own way, and readers do enjoy genre mashups where familiar tropes are recontextualized – but they still want to know what ingredients are on the plate.
Stories do 'change lanes', starting as romance then turning to thriller, but the tin will be labelled 'romantic thriller' or more likely just 'thriller' as the dominant genre with the romantic aspects clearly signaled through the title, through the dust jacket, through the cover art, through the blurb…. You want customers to know what they are buying.
Stories can't really lie about their genre and still be that genre. Every 'hint' and 'foreshadowing' is a tease to the reader that the other stuff is building – typically the 'dominant genre' is already happening in the story, but the protagonist is in denial – the woman in the romantic movie is oblivious that her boyfriend is a psychokiller, but the audience suspects it long before she does creating tension and suspense. Tragic events happen (her dog dies, then her sister), driving her to be closer and more dependent on the boyfriend. This works because the tragedy/dependency trope appears in both romance and thrillers– this is recontextualization that works! What's going to happen when she finally realizes she's in the wrong movie?
Notice the person who got fooled is the protagonist, not the reader.
Games have mechanics, not genres
Games are a completely different animal.
The core 'genre' of a game is its mechanics – how the player interacts with the game environment. I don't want to retread the 'ludo-narrative' debate, but games borrow tropes and ideas from literary and film genres for their stories, but the dominant structure is the game itself: survival, repetition, the 'action loop', the 'balance' of replenishing inventory as its expended, and adjusting to the player's skill level… there is no comparison in linear media.
Applying to your description, your game starts as man-against-nature survival, then ramps up with zombies. I'm assuming the game-mechanics are the same – so the game-genre doesn't really change – the player is still running and climbing and shooting, but early in the game the obstacles are rocks and the enemies are bears, later the obstacles are secret government medical facilities and the antagonists are an increasing number of zombies. For a game, this is a natural escalation. Weapons get bigger, enemies get smarter, but the game goal is still about clearing levels, picking up inventory, and exploring the environment – it never stops being that.
So, to directly answer your question, I think it's no problem for your game to escalate the stakes from a 'normal' enemy to a 'boss-level' enemy, over the course of the game. If you fight a bear early on, it makes sense you will have to fight a zombie bear later – zombie bear being the same type of enemy with higher kill points and different artwork.
I think you'd be fine to show the survival game and only hint at the zombies to come. Hopefully your story helps to bridge these stakes, and players have a good time shooting bears AND zombies.
Talos Principle – the Bait-and-Switch game
A personal anecdote, I bought a game called Talos Principle which presented itself as 1st-person photorealistic environmental puzzles. I enjoyed it while it was the game I paid for, despite the game teasing some metaphysical Lost-type of strange pseudo-mystery peppered throughout, which I was able to mostly ignore because I paid for the puzzles and stopped reading the mystery journal entries.
At some point, it became obvious there were easter eggs in the game that had NOTHING to do with the game. A goofy cartoon character began appearing – and I mean like Crash Bandicoot showing up in The Last of Us. Turns out the dumb cartoon character had a flying jetski that you can build and fly around on… for no reason? The artwork didn't match at all.
It was SO STUPID, I was SO OFFENDED, I was so DISENGAGED from the game that I lost suspension of disbelief in the environment puzzles. I stopped caring. The game I paid for was ruined, Rick-rolled by something looking like a sports mascot. Were the devs so bored by their own game they felt it needed some idiotic cartoon on a jetski? It felt juvenile, and it broke my trust that playing more would be worth my time.
There were hints and foreshadowing of another game layer, glitches and hidden trap doors – but metaphysical-spookiness does not add up to a goofball cartoon mascot.
There are plenty of other games that understand what they are trying to be.
First, I'm going to show you a basic outline for building up the twist and then give a couple of examples.
Phase 1-Ordinary Life
The world before the big twist is bright and idyllic. Everyone is happy, smiling. The tone is light and comedic.
Phase 2-Cracks begin to form
This is our inciting incident. Signs start to show that the world is not as perfect as it seems. Maybe someone goes missing or the protagonist starts seeing creepy shadows in the woods.
Creepy occurrences start happening more frequently. Perhaps more people go missing and more shadows start appearing. The tone gets darker but does not completely turn to horror.
Phase 4-The Reveal
The truth is finally exposed. The idyllic world has been shattered and the protagonist can never go back to living in ignorance.
Example plot-Zombie outbreak in a grim dystopia
Phase 1-Ordinary Life
In the perfect town of Smiles Burrow, everyone is always smiling and laughing. There is nothing wrong here. Ever.
Phase 2-Cracks begin to form
Ignore the cameras. Also, ignore the fences around the town. And the shadows that are outside those fences.
It seems Mr. Belle has gone missing. Oh, and his wife too. And their daughter. Everything's fine, though. Please, do not panic. Whatever you do, do not panic!
Phase 4-The Reveal
We told you not to panic, now look what you did! Okay, we have to come clean. This town was the last remaining city after a zombie outbreak. We have to keep everybody happy all the time because, if we don't they become a flesh-eating zombie. Forgive us. We can't let anyone know the truth, or they'll panic and become zombies. For the sake of humanity, we must eliminate you. Goodbye.
Start with the world being light-hearted. Add a few suspicious elements to make the audience question it right away. Increase the scariness slowly but surely to acclimate people to it, and then reveal the truth.
That is my suggestion.
I would think that any game advertised as 'survive the zombie apocalypse' would be considered at least horror adjacent.
I am assuming that you want the story for your game be not start with horror but to end up at horror.
That seems like you'd want to de-emphasize the horror aspects of the zombie apocalypse. I think you can do that if you effectively eliminate the element of zombie-danger from the start of the story/game. If the player is in the middle of the Gobi desert or in Little America in the Antartic, they'd rationally be relatively safe from a zombie attack while still be faced with the economic/logistic problem of staying alive. In the story, they've lost their life line to resupply because of the zombies impact on supply chain or destruction of society, but without the zombies on their doorstep, the horror would be minimized.
Then, later the story can evolve to phase II or IV as the zombies start wandering into the Gobi desert or swimming to Antartica and then the horror can begin.