Starcross

Starcross is the only Infocom game with an 'Expert' rating that I ever completed without any outside help. This was no doubt due to my near-limitless enthusiasm for hard science fiction at the time the game was released. Although no particular story was instrumental in helping me figure out the game's many puzzles, the background in basic physics and familiarity with hard SF space travel conventions were essential to feeling at home in the game universe.

The most notable feature of this work is its extremely consistent internal logic. There are no quirky or humorous solutions here -- though you may need to have a flash of insight to comprehend a particular puzzle's symbols or structure, the solution is always clear enough (if not necessarily immediately reachable) once this occurs. The author does a perfect job of providing you the information you need to solve a puzzle without making it instantly apparent which information is significant to which puzzle.

This game is definitely 'old school', and, as such, may seem unfair to someone more attuned to the modern IF style. It is extremely easy to make the game unwinnable without realizing it. Somehow, this fits the style of Starcross well -- you are exploring an unknown vessel full of alien technology, and it seems right that you must rely on your own intuition instead of an author-supplied 'revelation' that you just made a mistake. Sure, you should make use of the save command frequently, but, when you find yourself stuck, you should always be able to deduce where you went wrong after some reflection.

If you're an SF junkie, you'll probably love Starcross. If not, expect to feel frustrated and lost a good chunk of the time.