Nobody appreciates more than me a developer that tries to revive the old ways of video games. However, games today have to have mechanics that can hold your attention. NES sidescrollers are a dime a dozen, so it's no wonder that only a handful of them became popular with gamers. Oniken compares more to those random obscure sidescrollers when it should be more comparable to the memorable ones like Ninja Gaiden.
In honor of this game's admirable attempt to revive the NES era, I will review it as any magazine from the old days would.
Controls - 3/5 - Movement in Oniken is extremely fast which often leaves you little time to react to an enemy. Pressing up and attack uses a grenade, but pressing up while in the air halts your forward movement which can lead to accidental deaths when you push up.
Graphics - 4/5 - The cutscenes are decent, but the sprite animations are boring. The main character's run cycle is only about 3 or 4 frames. Backgrounds really capture the spirit of NES era graphics and are well made.
Sound - 2/5 - Music is acceptable, but has no melody to it and is easily forgettable. The sound effect you'll be hearing the most is the sword swing. Strangely, most of the other sound effects are barely audible.
Replayability - 2/5 - The game is extremely linear and doesn't offer any deviation from the main path. The only benefit of replaying the game is having an easier time due to prior knowledge of enemy placement and mechanics. Some secrets can be found in destructible walls.
I enjoyed the novelty of playing something that felt like an NES game on Steam, but that's about the extent of my enjoyment. Getting it cheap in a bundle is the only way I could recommend it. Paying full price is highly discouraged.