Just create a super detailed level that has custom karts, custom performance, custom weaponators, objects to 'grapple' with, objects on fire, water to your level, a track to change shape of, etc. etc. etc.
You can just look at the tutorials in a level by pressing the square button to open 'popit' and click on ''?" for the tutorials to help you create levels like never before!!
"Running a friend over is bloody painful, killing your friends from within, one at a time..."