What the format changes

There are two opponents in 2HG, so every 'each opponent' clause resolves twice against a single shared life total.

Forcing both opponents to sacrifice strips two boards for one card — the classic 2HG blowout.

'Each opponent discards' is a two-for-one in 2HG. Syphon Mind and friends jump several tiers here.

Teammates share one turn, so an extra turn is an extra turn for both players — double the value of the same card in a duel.

A wrath answers two developed boards at once. Sweepers are premium removal in 2HG.

'Target player' and 'target permanent' effects can be aimed at your teammate — you can't do that in a duel.

You're defending against two attacking players out of one shared life pool. Fog effects buy a full team turn.

Drain and burn that reads 'each opponent' comes off one shared 60-life total, so the printed number doubles.

Stax and tax effects tax two opponents for the price of one, while your team plans around them together.

'Whenever an opponent…' fires for two players instead of one, so these triggers pay out roughly twice as often.

Turns are shared and fast in 2HG. One- and two-mana answers let you hold up interaction without losing tempo.

A 2HG team loses at 15 poison counters rather than 10, so infect clocks are slower than the raw numbers suggest.

Shared draw feeds two opponents and only one teammate. The math is against you in 2HG.

Two opponents deploy two boards. Spot removal trades down unless it's cheap or hits multiple permanents.

60 shared life is a bigger pool than 20, so small lifegain is proportionally weaker — and it's the same pool your teammate is spending.

Cards that reference 'the opponent' or single-combat framing lose reach when the table has two opponents.

In 2HG the monarch is held by a team, so the crown swings between two players and is much harder to steal back.

Anthems only pump creatures you control — your teammate's board is untouched, so they're worse than they look.