Bugs:Dr. Mario (Game Boy)
This page details bugs of Dr. Mario (Game Boy).
Level Generation Bug
It is possible for the game to get stuck in a loop trying to populate the board with viruses, especially on Level 20 or later. This is caused by the assumption that N viruses will be placed on the board. The game will continually iterate over the board trying to place viruses, and doesn't know when to stop because the only condition to stop is when there are N viruses.
A proposed fix would be to count the number of iterations taken, something conservative like 10,000, and stop if that or the N viruses condition is reached.
A video of the glitch in action (taking place on Level 28 in this case) can be seen here.