This game is a retro-styled action platformer that pays heavy homage to the 8-bit era, especially NES classics like Ninja Gaiden. Its pixel art, chiptune soundtrack, and cinematic cutscenes capture the feel of late ’80s gaming, and the developers clearly aimed to recreate both the look and difficulty of that time. I highly recommend looking into the other titles of the same developers if you like this kind of game, since they are all similarly good, very high level if quality nostalgia.

The game is known for being challenging but generally fair. Levels introduce hazards and enemies in a way that allows players to learn patterns, and boss fights are intense highlights that reward precision and memorization. Controls are tight overall, giving combat and platforming a satisfying sense of responsiveness, though some minor quirks, like crouching, can feel less polished. This is a very good title if you like challenging changes, and also if you have the completionist mindset, since it is short enough to enable you easy NG+ replays.

On the downside, Oniken is a fairly short experience, and once the learning curve is conquered, runs can be completed quickly. Its adherence to retro design also means it leans heavily on familiar tropes. Overall, Oniken succeeds as a love letter to classic 8-bit action games. It offers tough but rewarding gameplay, stylish presentation, and memorable boss battles, though its brevity and retro quirks may limit its appeal to players who expect modern conveniences. This feels like a proper reading of this genre in today's standards, technologies and game balance.