Viewtiful Joe Double Trouble - Platform: Nintendo DS V-Rated mode: ------------- Successfully complete single player mode under the Adults difficulty setting. Defeating Bosses: ----------------- One technique that is particularly helpful against most of the Boss stages is to use the Slide attack. Use Slow + Slide repeatedly. This does a decent amount of damage in a short time. You can hit the Boss four to eight times if you are fast enough, while the Slow adds more damage to each attack.