Colossal Cave 550 follows the classic Adventure loop:

1. Exploration
You navigate a non‑linear cave system, discovering new rooms, hazards, and treasures. Movement is described textually, requiring careful mapping.

2. Puzzle Solving
Puzzles range from:
- object‑based (use item X in location Y)
- environmental (crossing chasms, navigating mazes)
- creature‑based (dragons, dwarves, ogres)
- logic puzzles unique to the 550 expansion

3. Treasure Collection
Adventure 550 includes 26 treasures, significantly more than the original.
Examples:
- Golden chain
- Persian rug
- Rare spices
- Gem‑encrusted helmet
- Platinum pyramid
- Casket of opals

4. Survival & Hazards
- Dwarves attack randomly; you must defend yourself.
- Pirate steals your treasures unpredictably.
- Ogre blocks progress in expanded regions.
- Environmental dangers: pits, rivers, mazes, dragons.

5. Scoring
The game awards up to 550 points, reflecting:
- treasures found
- puzzles solved
- exploration milestones
- survival and special achievements

Credit:
Will Crowther · 1976
A programmer at BBN Technologies and devoted spelunker, Crowther wrote the first Colossal Cave Adventure to share his love of Mammoth Cave in Kentucky. Running on a PDP-10, the original game modeled real cave passages and is widely considered the founding work of the adventure game genre.

Don Woods · 1977
A Stanford graduate student who discovered Crowther’s game on ARPANET and, with his blessing, expanded it into the 350-point version known worldwide. Woods added treasures, puzzles, fantasy elements, the troll bridge, and the magic words XYZZY and PLUGH.

David Platt · 1979
Extended Woods’ version to 550 points, adding the catacombs, ice caves, new treasures, and richer puzzles — creating the definitive full-length Colossal Cave experience.