To obtain bruUGHNO you must... Edit
Go to the Presumed Dead ending, wait until the end of the credits, and then click on the moon.
Go to the docks of the Ghost Inmate ending route, go to the docks and use the Shadozer. Then, click the moon.
Finally, again, go to the Presumed Dead route, specifically to the Transfer Cells Blockade, and when you see the Mario Kart item box as an option, (it will pop up as "Item") click it as quickly as possible before it stops spinning with options. You will see the bomb reference from "The Impossible Quiz", and that will be the last thing you need to click so you can get the bruUGHNO medal. Hope this helps!