Screencheat

Screencheat is the most on-concept split-screen game ever made. Every player is invisible. The only way to find opponents is to look at their section of the divided display. The whole mechanic is built around the thing split-screen players are usually told not to do. I tried this with my regular group on PC and the first twenty minutes were chaos, not the fun kind. Then someone figured out how to track movement patterns and suddenly it clicked into something genuinely clever. The studio that made it has since closed, but local play still works. Niche, but worth knowing about.

The concept is the joke and the joke is the game: everyone is invisible so you have to screencheat to figure out where opponents are. I've watched this game turn a room of moderately tired LAN attendees at midnight into people who are suddenly very awake and arguing. It's not a serious shooter and it doesn't pretend to be. Screencheat missed the top ten because its gameplay depth is limited and it works best as a session break rather than a main event. But if your LAN needs something funny and immediately readable that absolutely everyone can participate in without explanation, this is the pick.