5 tongue-in-cheek game writing exercises that are a more realistic representation of what most game writers do (in my experience) than a branching dialog tree:

ONE: You're writing ultimate ability lines for a hero character in a pvp game. Her personality is "hot valkyrie with a katana." Write 20 lines for her, no more than 3 seconds each when spoken aloud or your audio director will hate you because she's chattering over gameplay.

TWO: The player can unlock 20 different motorcycles. Name each motorcycle and write a lore blurb for it that is no longer than 80 words. The only thing you can visually change about the motorcycle is its color, the model is already locked and is identical for each motorcycle.

THREE: Write a script for an NPC meant to help guide players through a tutorial. The NPC needs to be hilarious, not break the fourth wall, and also instruct the player on these subjects: how to fish, do a backflip, and change their graphics settings.

FOUR: This NPC will ask the player to kill 40 forest wolves, 9 times. Write a short blurb that explains why this NPC needs the player to kill 450 forest wolves for some reason. Make it heartwarming, bleak, and memorable, but also keep in mind 98% of players won't read it.

FIVE: We have a level. It's already fully complete with final art. It's an island with a volcano made out of literal donuts. Please write the intro VO a NPC will speak to the player which explains volcano donut island. No, it can't be funny. This game is extremely serious in tone