Just FYI, that first Dante gameplay video skips the cutscene before the boss fight but shows the one after, which might be why it got removed from IGN.
The more I watch of Dante in this, the more I think that Dante's character in the second game is now part of his intended character arc. The games have never really hid the fact that Dante is dealing with some major trauma from all the crap that's happened to him. I don't think that I'd go as far as saying that his fun-loving aspects are just an act, but it's kinda telling that the only time he really lightened up in 2 was when he was fighting, and that seems to be the case in this game, too. There's points where Dante is between fights and just seems... weary. And he's gone from using rigged coin flips as an excuse to help people to actively avoiding his own allies.
Going in chronological order, his parents were killed in childhood, his brother killed masses of humans in a bid for power, dropped into hell rather than let Dante save him, got lead into trap by a woman that looked like his mother, fought his mind controlled brother, who then exploded, then the demon clone of his mother seemingly died, then he encountered his dead brother's previously unmentioned son, which couldn't have brought up good memories.
With all that, the real question is whether he decided to become a coin-flipping weirdo before or after trying to drink himself to death.
Hmmn. The IGN footage showed Dante fight a miniboss wearing Nelo Angelo armor. I don't think that Vergil has gotten any less dead recently, but it looks like at least one of the factions is using Mundus' old gear.
Unfortunately, fools are often planproof.