Dr. Mario Cheats - GameBoy
Primary Collection of Cheats
Bonus objects
Play virus levels 5, 10, or 15 at medium or high speeds.
Wait at the intermission screen that features three viruses in
a tree. A bonus object will appear at the top of the screen. A
different object will appear depending on which level and speed
is currently being played.
After completing level 20 on medium or high speed, an object will
fly above the little viruses on the tree.