The mere fact Kaiji Tang has to say some masculine-sounding "Pikas" when no one but Tim understands Pikachu.
Any time you fail at some specific quick time events will end up in Amusing Injuries for Pikachu.
Pikachu tries to make Manetric fetch a Frisbee, only for Manetric to pick his hat and toss it like a Frisbee.
Pikachu interacting with Baker's Accelgor. Pikachu tempts Accelgor with a donut, but it doesn't come out of hiding. Once Pikachu lets his guard down, Accelgor comes out of nowhere and steals the donut.
Detective Pikachu becomes curious at what's under Mimikyu's rag. Of course, he ends up being horrified.
Pikachu's half-assed attempt at using Quick Attack.
One of the prompts of Pikachu trying and failing to use a move has him trying to use Flamethrower, despite Pikachu not being capable using that move in general.
Some of the subtitles for Pokémon you can interrogate:
Rattata: Will go anywhere for food
Garbodor: A connoisseur of trash
Kriketune: Attractive middle-aged musician
While the at the studio Pikachu does his "bolt of Brillance" line on camera, startling the guy who was in the other room watching the cameras to fall off his chair in shock. This is followed by Pikachu's line about who the culprit being interrupted by Mimikyu pushing him off camera.
If you choose to put "Move In" in the third slot while you're filming Pikachu on the Yanma Cameras, Pikachu will roll into the camera.