Play Heiankyou Alien (Japan) Online

Heiankyou Alien came out on the Game Boy in 1990, developed by Nintendo R&D1. It was a portable version of a much older arcade game, fitting right in with the kind of simple, focused puzzle-action titles that were common in the system's early years. You don't see many games like this anymore, where the entire concept is built around one clever mechanic.

You control a little security officer tasked with protecting the ancient capital from aliens. Your only tool is the ability to dig holes in the ground. The goal is to lure an alien over a freshly dug pit, trapping it temporarily, and then you must quickly fill the hole back in to defeat the captured creature. The challenge comes from managing multiple aliens at once; they learn your patterns, move faster as stages progress, and can even climb out if you're too slow. It starts calmly but quickly becomes a frantic exercise in spatial planning and quick reactions. The satisfaction comes from successfully setting and springing your own traps, turning the environment against your foes.