[BWTraveller]

Maybe "healing" would be a better term than redemption. He's in a dark state and it's looking to get darker, and it's about him getting out of this bad place. Either way, I feel like calling this a "revenge story" is like calling Erased a "whodunnit": it has some minor resemblance on the surface but viewing it that way completely misses the point. Satoru from Erased wasn't there to catch the bad guy, and Naofumi's story is not about getting back at those who wronged him, and if you watch either of those shows expecting that to be the plot or the conflict you're going to wind up disappointed at how much it "fails" to deliver that which it didn't mean to deliver in the first place.

And no, it's not just "common sense" to insist that you're clearly not in a game or a dream or anything of the sort when you find yourself in a place that makes absolutely no sense by your understanding of reality but closely resembles a game. In fact there have been very good fantasy series written by American authors as well in which one of the plot points for a long time was the hero's belief that he's in a dream and the question of what it means morally for him to insist on that conviction, as well as the redemption and healing after he realizes that it's real and what that means about his situation and actions. Again, it may seem like "common sense" to us on the outside who know we're looking at fiction, but to a guy who has a firm separation between the game and real world it'd be difficult to recognize that anything in the world is different from the game they think they're in. I'm not saying those guys are smart, I'm just saying that they're not all that unbelievable.