Perhaps the greatest of all the grand 3D 16-bit adventures, Damocles has a particular atmosphere that has stuck with me years after I first played it. There's something about the solitude of it... a last man on Earth vibe that's incredibly eerie and appealing at the same time. The completely deserted yet fully-functioning solar system is vast and invites exploration, however, a ticking clock is there to constantly remind the player that this place is doomed without their timely help.
It's design dictates that Damocles is a very open-ended game. Almost from the start you're able to go pretty much anywhere you want, so it's a case of thinking the puzzle through and assembling the means to avert disaster - and the game offers five different solutions, each with their own consequences and rewards. The ideal solution is to change the course of the comet Damocles, so as to save the planet Eris and leave the comet intact for study, but there are other options. There is even a rudimentary trading system in place, which has to be exploited for the player to gain access to some of the more vital items.
Damocles is no action game. There are no enemies and you don't even carry a weapon. Looked at in the most basic terms it's an inventory puzzle on a massive scale, but it's that sense of a solid, consistent, but ghostly environment that sticks in the mind and makes it a classic.