TimeTrap

In this game, you are a scientist who is researching time, when you discover that hidden nuclear devices recently planted by terrorists will detonate 23 of the world's most populous cities, including your own. Thus, you have to use your in-development time travel machine to save the world: you can go forwards and backwards in time, and different buttons you press determine how far you go. The readme says that it was inspired as both a return to the mid-1980s Infocom age and a tribute to Golden Age science fiction. It was also the author's first time making interactive fiction, and the game came out really polished and well-written.

The opening segment of getting to your laboratory and fixing your time machine has some standard, easy puzzles. After that, the game is supposed to open up, but much of the midgame is unfinished. There are no NPCs or goals programmed in, and most time periods consist of wandering around until you get lost and/or die. Still, it's clear that the author had a lot of plans that likely would have worked out if they were implemented. It's a shame that this game wasn't finished, because the writing style and premise are engaging.