On Desktop / Mac / Web app
Step 1: Open the game preview screen.
Step 2 : Under the previews, you can see a delete button.
Step 3 : Tap on delete button and it will delete your game.
On Mobile app :
Step 1 : Open the game summary screen
Step 2 : Tap on three dot (…) button and it will open different options.
Step 3 : Tap on delete button and it will delete the game for you.
NOTE: Once game is deleted, it cannot be recovered.