They really skip over what makes Onimusha cool, and focus on Musashi (a legendary historical samurai).
Unfortunately, there's no collecting of genma souls to upgrade swords into progressively cooler versions, there's no creepy castle full of monsters, and for some reason the oni gauntlet is seen as a burden or dangerous which is the complete opposite of normal Onimusha lore.
It's a real shame, fans of Capcom's series won't find what they're looking for here, and the average viewer isn't going to be sucked in by a bunch of bickering samurai fighting what appear to be bog standard zombies and a few demon things peppered in.
It's another case of trying to water down an existing IP to broaden appeal, using cheap CG instead of quality animation, and making nobody happy in the process.
Your time would be better spent actually playing Onimusha: Warlords.