Causality is a Z-machine 5 interactive fiction game written with Inform 6 and is © 2003 by Hugo Martay.
Review by David Welbourn (originally posted at Baf's Guide)
Something of an epic tale, you play a mysterious someone who pops about the spacetime continuum by unknown means, to sabotague spaceships, laboratories, and warships that need sabotaguing, sometimes to partially counteract your own actions in previous (or subsequent) identities.
Despite its scope, the game is easier than you'd think, since your current goal at any time is often spelt out, each individual scenario is fairly small, and there are few real obstacles between you and success. It's not that difficult a game.
On the other hand, the game suffers from a severe lack of polish. Objects are weakly implemented, grammar and punctuation are quite poor, and the entire backstory of who you are, where you came from, who you're working for, etc. is left totally unexplained. I'd play another game from this author, but I hope he gets the aid of a beta-tester and proofreader first.