Though ostensibly horror-themed, Dr. Chaos is a rather straightforward 2D platformer that has the player control a character named Michael Chaos as they explore a decrepit mansion and defeat waves of enemies. As well as the four floors of the mansion, the player can also explore additional areas through warp zones found in several of the rooms.
It's most notable aspect is when the game occasionally assumes its "adventure game" mode whenever a door is entered: The player must use a finger cursor in a first-person perspective to check cupboards and other areas for additional items and hidden passages. These sequences have a passing resemblance to the first-person sections of The Goonies II, though given that game had only just come out at the time it's likely the similarity is coincidental.
"As Michael Chaos, you must infiltrate the mansion where an experiment of your brother's, Dr. Ginn Chaos, has gone horribly awry and brought extra-dimensional demons to this world, to close the portal and save your brother before it's too late."