Revealing mistake: During Kenjiro's fight with Phan Xu, Kenjiro cuts Xu's face. This cut goes across Xu's headband, but the headband is still in one piece. The cut is visible above and below the band, but the band itself is untouched. As Kenjiros sword is capable of cutting a steel chain, a piece of cloth should not pose any difficulty.
Continuity mistake: During the final battle between Kenjiro and Collins, Collins starts out wearing a black kimono with white trim, similar to the one Kenjiro is wearing. However, several times during the fight, he is seen wearing the simple blue kimono (without trim) he has used in his earlier fights. His outfit keeps changing back and forth during the entire fight, sometimes black and white, sometimes blue. The absence/presence of white trim makes this very easy to see.