Unfortunately, resetting your game progress is not supported for BattleBlock Theater.
We found this feature caused some issues in previous games (like users accidentally resetting their save progress and then being pretty sad!) so we chose not to include it this time around.
You do get four chances to play through the game and get the movies to trigger, as Solo and Coop in each difficulty (Normal and Insane) are considered different progress files.
All the movies are also neatly organized in the Movie Theater once they're unlocked, so you can always replay them at the appropriate times if you want to relive the magic.