Some players think that video games are created by tugging on a series of levers, like Homer Simpson at the Springfield nuclear plant. They believe that changing something inside a video game is as simple as pushing one of those levers into position and sitting back with a donut. If a developer wants to add co-op, simply push the “add co-op” button in Unreal Engine. Easy peasy.
Obviously, this is fantasy. The reality of making a game work in co-op is a nightmare. When one player is looking around your level, you know exactly what assets you can cull to save memory and what assets you can’t. Add two players or more and, whew, it gets a lot more complicated. There are also a bunch of other factors to consider, but this isn’t an article about co-op. No, this is much more interesting. This, my friends, is an article about doors.
Game developer Liz England once wrote a brilliant essay called The Door Problem, which outlines exactly why doors are such a pain in the ass for game developers to implement. Doors aren’t simply a passage into another room – adding a door creates a series of design problems. Can the AI also go through doors? Can doors be blocked, preventing the player from progressing? What happens if an AI gets stuck in a door? And on and on and on.
