8 Eyes, developed by Thinking Rabbit and published by Taxan for the NES in 1988, is frequently and fairly described as a Castlevania-inspired action game. You play a warrior exploring a series of castles set across different regions of the world, whip-and-sword combat giving way to platforming and boss fights against guardians who hold the titular jewels.

Its standout feature is your companion falcon, Cutrus, which you can send out to attack enemies and reach spots your own weapon cannot, and the game supports two-player co-op with one player controlling the hero and the other the bird. That shared-control idea was unusual for the time and gives 8 Eyes a distinct identity beyond its obvious influences. It has a reputation for being demanding, and modern players will find the difficulty and slightly stiff controls a hurdle, but it remains an interesting and slightly overlooked slice of the NES action library that rewards patience.