Dr. Mario

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.

Hint: Super Mario Bros. music:
If you destroy a combo of four or more, a siren will start, then the music from Super Mario Bros. will play.
Information in this section was contributed by Augusto.