Armor percentage rollover

In versions of Doom 1.2 and earlier, armor percentage was not limited to 200. Since the armor count in the status bar has only three digits, the display can wrap around to 0 percent if enough armor bonuses are picked up to reach the thousands column.

Technical
There is no set limit to the amount of armor that a player can accumulate in these versions of Doom, so theoretically, a player could overflow the signed integer variable for the armor percentage, and consequently have a negative amount of armor. However, the limitations of the WAD format make it impossible to construct a level or series of levels containing the billions of armor bonuses necessary to cause such an overflow.