Smart terrain causality chains for adventure-game puzzle generation

Adventure videogames have the player assume the role of protagonist in an interactive story, which is primarily driven by exploration and puzzle-solving. A major drawback with this genre is minimal replayability, since the player has already seen what there is to explore, and knows how to solve the puzzles. We propose a technique to generate variations on puzzles that fit in the same location in the original story, and therefore don´t require fully procedural story generation. We keep a database of smart terrain items, which can have effects on other items. Puzzles are generated by taking advantage of a duality between puzzle-solving and generation. Once we build smart terrain causality chains (STCCs) of puzzle solutions, a puzzle known to be solvable can be generated by simply inserting the items contained in a causality chain into the environment. We demonstrate this technique in an experimental videogame, Space Dust, which shows that even a very short adventure game can produce multiple interesting playthroughs when STCC-based puzzle generation is added.