Bowling for Bots: In Skytown, if you use Morph Ball to run over the Tinbots, you'll gain this bonus. Easiest place to do this is in the doughnut-shaped room.

Stylish Kill: In Skytown, there's a Bridge area that collapses when you cross it. Before it falls, there's a fight with Tinbots and the Master Bot. Ignore them and finish crossing the bridge. A cutscene with go off and show the bot fall to their doom.