Dr. Jekyll and Mr. Hyde is a side-scrolling action game where the player takes on the role of Dr. Jekyll and Mr. Hyde. Players are trying to reach a church to wed Miss Millicent. Along the way, townsfolk and animals will cause damage to Dr. Jekyll. Accumulate too much damage at one time and he transforms into Mr. Hyde. When this happens, it becomes night time and Mr. Hyde will continue onward as long as he causes damage. Don't do enough damage, and he transforms back into Dr. Jekyll.
The game has 6 levels and 2 endings dependent on which character the player controls when they arrive at the church.