"Wrong" here can be intentional or unintentional. Maybe you completely missed that a character had a certain ability and got through the entire game without knowing there was so much more you could be doing! Instead, maybe you specifically challenged yourself to get through the game without using that ability, seeing if you were up to the challenge! Maybe you activated cheats to cruise through on easy mode, or maybe you accidentally activated a cheat and had no idea that the game wasn't supposed to be that easy (ask me about my FF7 playthrough).
"Wrong" can also be however you decide to interpret it: counter to the developer's intentions, exploiting the game engine, uncovering a loophole in the game's systems, pursuing your own goals instead of the game's goals, etc. It's not meant to be a moralistic judgment by any means (play any game however you want!) but more just an identifier that you went against the game's standard norms and expectations.
Tell us what you did "wrong", why you did it that way, and what the outcomes were. Did it make the game more fun or exciting? Did it ruin the game for you?