I just released a one-shot demo of my tabletop game Psychics, Bullets, and Swords. This one shot takes about 1-2 hours of play, has easy to learn rules, but creates complex encounters when the players try to kill each other's characters while using the environment and weapons they find.
The full game is a RPG / Wargaming hybrid, while this one-shot is closer to a small wargame. Hope you enjoy it.