Each player has a "Goal"

[KaiGeffen]

In addition to removing all of your opponent's units, each team has an alternate way to win that they decide before playing.
This victory condition is not known by the other player.

Possibilities:

• Have all of your units deployed
• Have the game last for 20 turns

Be sure that this feels fun and diversifies the game. It can be tested without writing any code.
Goals might need to be publicly known.

[KaiGeffen]

It's possible that instead/in addition to this, certain moves/classes/objects will allow you to win.