I tried a 2 on 2 game with a single board and needless to say, it was pretty chaotic. It was two players playing with two spellbooks each. Teams lined up on the same row (with one row in the middle as kind of a neutral zone). I would assume that things would change depending on the play style of course, but here was my experience.
The game quickly turns into a more of a territory battle.
Conjurations get destroyed almost right after they are summoned.
There's no such thing as an expendable creature or conjuration. You lose something, you lose your footing, and that's a huge deal.
To guard or to attack? You will be spending hours pondering this; you need both a strong offensive and defensive strategy at the same time. Sorry, there's no other way to explain this, it was kind of surreal being in this situation pretty much the entire game.
Mages took a much bigger combat role than what I was used to. Usually one fights, while the other builds up or supports, then they switch and it just goes back and forth like that.
Zone Attack spells are more dangerous than ever before, you have to spread out and you HAVE to be in your opponent's territory to discourage your opponent from casting them. Do anything you can to mitigate the power of these spells.
The "Slow" trait isn't such a big deal anymore. You're never too far from a Hydra.
In fact, you're never too far from anyone. There's always a bowman or some kind of ranged attacker that can hit you.
It takes forever to plan all of this out and make all of your moves, but in terms of number of turns, the game is noticeably shorter than 1 on 1.
Therefore, it would probably be a good idea to stock up on Dispels, Dissolves, Heals, etc.
Anyway it was just one game and it was an interesting experience. Doubt I'll do it again anytime soon though as it took a very long time.