This gif is demonstrating the third "Team" action in my game, the Team Move action. For me this is one of the most exciting potential uses for the team-up mechanic. The initial seed of this game's idea was what kinds of things you could do if you could have a unit perform an action simultaneously not just with its closest neighbors, but also its neighbor's neighbors. So you could theoretically have a line of units all taking part in the same action, or even in formations like in the gif.
I'm excited to come up with scenarios that encourage this kind of play! And I'm currently working on the (to me) most exciting "Team" mechanic, and once that's done I'll finally be done coding all the player actions!
