This took me forever to get.
Sweepin’ Time Achievement Guide
I used Classic Style with Hard Mode turned on.
I highly recommend Hard Mode as it makes it harder to escape Gotta Sweep, making it easier to get the achievement.
After getting the second notebook, turn right and go to the faculty rooms. Go through the rooms and when you exit, go to the left and get a BSODA from the machine (assuming you have the quarter from answering the notebook), then go into the long hallway into another faculty room where there will be a quarter on the table. Grab it, then head to the cafeteria, where there will be a BSODA on a table and another BSODA machine.
I recommend getting 3 BSODA’s for Gotta Sweep, but you can also get other useful items like Zesty bars, WD-NoSquee’s and Safety Scissors (incase Playtime or 1st Prize appears)
Now head to Gotta Sweep’s closet, and wait until Gotta Sweep starts moving.
Gotta Sweep Started Moving
This section is heavily RNG.
Now that Gotta Sweep started moving, if he goes into a really long hallway, use the BSODA’s you have to push Gotta Sweep to the end of the hallway to push him back, and just try to stay on for a few more seconds and you will most likely have it. If you do have the third BSODA, use it again and you will definitely have it.
If Gotta Sweep starts going into rooms, try to be around the middle or right of Gotta Sweep to try to prevent yourself from falling off.
If you start to lose Gotta Sweep, you will have to run in order to catch up, as if you fall off, it will reset the time.