Play Jangou (japan) Online

Jangou was released only in Japan for the Nintendo Entertainment System, though I don't recall the developer. It's one of those many NES titles that never made it overseas, a product of its time when the console's library was expanding in all directions.

You control a character navigating through a series of single-screen rooms, each one a self-contained puzzle or combat scenario. The main goal is to progress through these rooms, which often requires finding a key or defeating all the enemies to unlock the exit. A signature mechanic is the screen-by-screen exploration; you move from one static screen to the next, and each new room presents a fresh challenge. Another is the combat, which involves using a sword or similar weapon to fight off various creatures. The game can be quite difficult, with enemies respawning and the need for precise movements. It feels like a methodical test of your patience and reflexes as you work your way through its challenges.