When you're not being assaulted by awkward vocal exchanges, you kill lots and lots of boring zombies. The combat has only a hint of the series' fast-paced, ninja-slicing prowess and is often bogged down by uneven difficulty spikes, frustratingly problematic hitboxes (which allow enemies to damage you without actually touching you), and rampant repeat enemy encounters. You need to quickly dash across the battlefield to avoid damage and string together attacks for huge combos. There's also an ability to execute element-based super zombies, then rip off their arms and other body parts to acquire special elementally-charged weapons. Mixing the zombies' elemental powers and pulling off the combos to rack up a massive hit count is sometimes entertaining. You can use an electricity-based weapon against a poison type enemy to instantly freeze it in a crystal, or send a jolt of electricity through a fire-type enemy to create a devastating plasma storm that kills everything in the immediate vicinity. But then comes the camera, which often has trouble keeping Yaiba on screen, or zooming in enough to actually see what you're doing.
Even though the combat system is passable, Ninja gaiden Z is severely lacking in enemy variety. After the early levels, you'll have seen just about every enemy the game has to offer. From there, NGZ simply throws more and more of these same enemies at you to increase the combat difficulty from level to level, forcing you to slog through a fight against 20 zombie clowns that you have already battled a dozen times before. The same goes for the boss enemies. You'll see the same two bosses repeatedly in the campaign and take them down with the same strategies you used in every other encounter. The bland combat then culminates in one of the most mind-numbingly tedious final boss battles I've played in recent memory.
To make things worse, Ninja Gaiden Z doesn't offer anything to meaningfully break up the dull combat. In previous Ninja Gaiden games, Ryu would be required to traverse the environment using his wall-jumping ninja skills. Yaiba has ninja agility too, but you don't have direct control over his movements. Instead, you wall-run, latch onto hooks with Yaiba's chain attack, and punch through obstacles as you follow one-button, on-screen indicators. The result is often a boring and frustrating experience as you attempt to time your jumps between instant-kill obstacles via awkward controls. Then there are the environmental puzzles that take little effort to complete and offer not even the slightest challenge. Most break down to finding a zombie and throwing it into a contraption that then opens a door. Nothing exciting there.
If you manage to look past the flaws and complete the game, you unlock the Arcade mode. This alternate mode reworks the game into a side-scrolling beat-'em-up, giving you the option to once again beat down on undead (as if you haven't done enough of that already). One highlight, however, is that the NES Ninja Gaiden soundtrack is swapped in for the level's music. But hearing the old songs is a small reward for going through such hardship.
Yaiba: Ninja Gaiden Z is a misguided button-masher that brings nothing to the Ninja Gaiden universe. The game contains little semblance of what made other games in the series great, and its dirty humor falls flat. While Yaiba's core combat abilities may be entertaining at first, the blatantly repeated enemies, boring bosses, and uninspired puzzle and traversal elements makes Ninja Gaiden Z the most unimaginative and monotonous entry in the series.