The Duel That Spanned the Ages is a fun mid-length sci-fi adventure about exploring an asteroid with a base and engaging with mechanical aliens.
Some people seemed not to like the infodump story at the beginning and end, but I enjoyed it. It was envisioned as the first story in a sequel, and I think people don't like being able to complete stories. But I've found that your imagination is often better than any actual sequels, and so the unfinished business was fine for me.
I couldn't figure out at first why this game was nominated for a best puzzle xyzzy when the first few scenes were completely linear. But when I reached the base, the game opened up and became really enjoyable. You have to figure out how to use a variety of equipment, including a giant mecha suit of armor, machine guns and rocket launchers, and medical equipment.
The game was not too long, and the provided map was very helpful. I strongly recommend this game.