It's pretty common knowledge that attacks get stronger in multi-player games. One thing that I haven't seen discussed is how the relative strength of attacks affects the strength of combos.
In two-player games, it's relatively easy to set up 2 or three card combos. Village-Torturer, Wharf-Fool's Gold, NV-Bridge, and HP-terminal Silver are common examples. These combos can often be supported by additional cards on the board, but usually the combo itself runs reliably.
In multi-player games, a lot of combos become harder to execute because of the increased strength/frequency of attacks. In standard drawing combos (Torturer chains, Wharf decks), discard or deck-junking attacks pose a far more significant barrier than in 2-player games because you're more likely to be hit by something every turn, which really slows your ability to pick up the linchpin cards. In addition, the additional turns you spend buying Silvers to get over the $5 threshold mean that it's harder to line up your combo once you finally have the pieces.
Conversely, combos that don't have to worry about those attacks, like NV-Bridge or Chancellor-Stash, become stronger on these boards because the deck junking/decreased handsize doesn't matter as much, which means these combos are more powerful vs. the attack than they would be in a 2-player match. Consider Sea Hag vs. Chancellor-Stash: sims give the two-player matchup to the Sea Hag player 74/23, while a three-player game with two Hag players against Chancellor-Stash gives the win to Chancellor by a massive 62/17.5/17.5! Sometimes the result is more modest: Witch has a 53/46 edge over NV-Bridge in 2-player but NV-Bridge against 2 Witch players is a virtual three-way tie.
The point is that, when evaluating combos, trying to connect cards in multi-player is trickier than in 2-player. So, combos that don't require cards to line up become more powerful. Hunting Party gets crushed by Village-Torturer in 2-player, but because it doesn't require the Hunting Party to be drawn with the terminal Silver, the HP deck edges out Torturers in a multi-player game.
Examples of combos that get stronger in multi-player: NV-Bridge, Hunting Party-terminal Silver, Chancellor-Stash
Examples of combos that get weaker in multi-player: +actions/+cards/+payload, Herbalist-Phil Stone, single-card engines like Minion or Governor