Age of Empires: Definitive Edition

Set up a game with a full tech tree, huge map, large resources, and post iron age. Turn on the 'steroids' cheat. Have your villagers build a bunch of houses and an Academy. Make a bunch of Centurions, select a large group of them by clicking and dragging your mouse over them, and press delete. This will instantly kill all the ones you selected. Rinse and repeat.