- Anti-Climax Boss: Part 2. Tatsumaru is surprisingly easy to beat compared to the sub-boss Genbu.
- Complete Monster: Onikage, chief servant and Psycho Supporter of the demonic Lord Mei-Oh, is a sinister undead ninja who went by the name Suzaku when serving the ninja revolutionary group The Burning Dawn, where he subtly manipulates the group and assists in its brutal actions. When his own lover is mortally wounded by the hero Rikimaru, Onikage ruthlessly kills her, declaring he has no love for weakness. Later assisting the rise of Mei-Oh with massacres and assisting evil cults in murders and transforming innocents into monsters, Onikage continues to return and engineers another war, with Rikimaru forced to kill over and over again. Killing and replacing the adviser to Lord Gohda, Onikage ends up burning down one of Gohda's castes, revealing himself when he takes Gohda's daughter Princess Kiku hostage and forcing Rikimaru to stab through her fatally to kill Onikage himself. Obsessed with the darker side of human nature and creating a world of chaos and carnage, Onikage repeatedly proves himself to be Tenchu's darkest villain.
- Friendly Fandoms: With Syphon Filter and Metal Gear series.
- Hilarious in Hindsight: The series features a sword called the "Izayoi", the ancestral weapon of the Azuma clan that seems to possess some degree of magical power. Many years later, BlazBlue ends up featuring a weapon called Izayoi that is also an ancestral weapon (Of the Yayoi family) that also possesses magical abilities. At least Tenchu's Izayoi doesn't blind its user.
- Moral Event Horizon: Tatsumaru massacring the quarantine village and the Azuma village.
- Narm: The English dialogue veers into this from Onikage's heavy Japanese accent (part 1) to Rin's inane screaming. There's also the geysers of blood that sound like whoopee cushions when someone dies.
- Ayame's infamous "Your arrows are like you: weak and twisted. I fear them not." Her voice actor reads the last sentence as a sarcastic. "I fear them...NOT!"
- So Bad, It's Good: The English dub.
YMMV / Tenchu