Once you collect the five crystals from the five levels in the Jungle Warp Room, you can fight Ripper Roo. Ripper Roo starts off by jumping around the area, leaving behind TNT panels. Stay away from them and wait for them to detonate. Just hang on for now. You can’t hurt the boss yet, so stay back.
Next, Ripper Roo drops nitro panels. Stay in a corner to avoid them. After they detonate, Ripper Roo is stunned. Move in and hit him with a spin attack to inflict one damage on the boss.
Ripper Roo repeats his tactics, again planting TNT and then green nitro panels. The best position for you is in the lower part of the area. Stay away until the nitro blows up, then move in for another spin attack against the stunned boss.
For the third phase, you must move around to avoid getting jumped on or running into TNT panels. After they explode, stay away from the nitro panels. When Ripper Roo is stunned again, move in for the final spin attack to defeat this boss and earn the “Professor Pulverized” award. Then continue to the next warp room.