Known issueFixUpdated · 2 replies on Steam
Phantom Blade Zero: With the Tiger Cannon Boss: An Instant Kill (Workarounds)
Short answer
No confirmed fix yet. Players suggest: I ran away from him and spammed dodge like crazy - it worked somehow (on the 4th try, duh)
The problem
BUG WITH THE TIGER CANNON BOSS: AN INSTANT KILL (ONE-HIT KO) OCCURS DURING A SPECIFIC ATTACK—EVEN WITH FULL HEALTH AND ACTIVE DEFENSES, THERE IS NO WAY TO ESCAPE.
What players suggest
If you mean red cannonball attack when he is 0 hp - it is intentionally made to kill you, because *spoiler*. I ran away from him and spammed dodge like crazy - it worked somehow (on the 4th try, duh)
Did this work for you?
Source: original Steam Community discussion. Quotes are shortened; all credit goes to the posters.