Power fantasy
Also said as Empowerment, Horde mode feeling
Designing the game so that the player gets to feel overwhelmingly strong. The enemies exist to be swept aside.
It is a legitimate pleasure and a tired player may want nothing else. Done without any contrast it goes flat, which is why many games make you weak first, so you have something to compare with.
Say it
“For the last hour, stop scaling enemies. Let the player one-shot the things that killed them in hour one, so they can see how far they have come.”
Where you’ve seen it
Vampire Survivors starts you weak and ends with the screen full of your attacks and enemies evaporating in crowds. The Dynasty Warriors series has built itself on one fighter against hundreds.
Not to be confused with fiero
A power fantasy gives you the feeling for free. Fiero makes you earn it. Plenty of games move from the second to the first as you level up.