Nothing we haven’t seen before,just duelyst 2 versus 2 style.
It can be used in the same board,with every unit being able to move only one square,all players starting at 2 mana,all players gaining mana and drawing cards at the same time,etc.
Passing through friendly units allowed,shadow creep counts for both players (mua ha ha,since its friendly)
and the list can go on forever.
EDIT: Player’s turn should be reduced to 45-60 seconds for fast-paced gameplay and to make things spicier. (You wanna swarm? jokes on you)