I set this game up to give my students a engaging way to review complex numbers. The nice part about it is that you can use it for whatever time period works for your lessons and class, so it could be a filler when you have that surprise fire drill and return to class with only 15 minutes left or when you decide your students need a little more practice/reinforcement. I've used the same idea for other content and am impressed by how much effort the kids are willing to make when it's a game. I only use a few minutes to review the Complex Number Game rules because I use this after my complex numbers unit but you could also start with an activity about complex numbers and then use this to reinforce the lesson.
I distribute the gameboards and markers, then set the time for the first round of games (5-10 minutes, then let my students play while I walk around observing and serving as mediator if necessary. (MP1) After the designated time, I call for a stop in the play and tell my students that they will now shift partners. We continue through as many rounds of play as there is time for, rotating partners after each round. When there are about five minutes left in class I call for the end to the final round and collect the materials.
To close this activity I ask my students to reflect on whether or not they feel more confident about complex numbers than they did before the game. This opens a general class discussion about the value of this kind of activity and provides me invaluable feedback about the way I structure my lessons.