Below is what I ended up settling on for an entry for the JS1k. My ideas ranged for a rainbow road (similar to the Mario Kart level), to a 3d tombstone that said dysentary, a terrain generator, then a wave generator. I ended up just combining the last two ideas and came up with below.
Theres really no terrain generation, its just the y value set to a random height. I just didn’t have the room in 1k to fit it in unfortunately.