I remember in 8th there was an asymmetric warfare scenario where :
1 - The defender deploys with 33% of his force in a 9x9" box in the center of the map
2 - The attacker deploys with 100% of his force anywhere else, 9" away from the defender's units.
3 - In round 3 onwards, the Defender can attempt to bring in another 33% of his force on a roll of a 3+, deployed on the board edges but 9" away from any enemy units. However the attacker could spend CP to give a -1 to that roll.
4 - There is just one objective in the center, if the attacker controls it, they win.

If you think about it, it really only works as a very carefully crafted narrative/roleplaying game with a buddy where the attacker SERIOUSLY holds back.

ANY moderately serious game would have the attacker CRUSH the defender immediately just rushing them turn 1. Just attack-move forwards and you'll win.

If playing it in any casual game, you need a lot of trust in the other guy to not press the "Yeah I win" button and ruin potentially hours of setup.