Bowser's Lava Lake Keep is filled with lava and it ends with you chasing after Bowser in your 2nd fight against him.
- Green Star 1: Go through the level until you see it. Slide down the wall then do some wall jumps to prevent your Italian plumber's death.
- Green Star 2: Just before you cross the bridge, climb up the wall to the left of it, and claim your Green Star prize.
- Green Star 3: Use the Boomerang Flower to obtain it, since it's in plain sight.
Once you blow up the wall with the P-Switch for the bridge, wall jump upwards until you obtain your Boomerang Mario stamp.