Dr. Jekyll and Mr. Hyde is a side-scrolling NES game loosely based on the original novel by Robert Louis Stevenson. Gameplay alternates between controlling Jekyll or Hyde, as they walk across town to reach Dr. Jekyll's wedding.

Dr. Jekyll and Mr. Hyde is an action orientated side-scrolling game developed by Bandai Co., first released in 1988 in Japan on the Famicom Disk System, before gaining a US release on the NES in 1989. The game is based very loosely upon the 1886 novel "The Strange Case of Dr. Jekyll and Mr. Hyde" by Scottish author Robert Louis Stevenson.
Story
The game's manual is left to explain the backstory; the game itself features no expositionary text to fill in what is going on. Dr. Jekyll has created a potion that has separated the good and evil aspects of his personality. When he is happy, he will remain as himself, but when he becomes angry, he is transformed into the homicidal and violent Mr. Hyde. The basic plot follows Dr. Jekyll's attempts to reach his wedding with the charming Miss Millicent, on the other side of town. Initially, he sets out from his house with his walking stick towards the chuch. Along the way, a variety of citizens, animals and other obstacles attempt to impede his progress, causing him to either become hurt and/or more angry. When his anger reachs a critical threshold, Jekyll transforms into Mr. Hyde, and the world becomes nightmarish alternative-reality. Furthermore, Hyde walks in the opposite direction to Jekyll, away from the church. If Hyde manages to kill the monsters and demons, his anger level returns to normal and Hyde morphs back into Jekyll. If Hyde does not dispose of the monsters or is attacked himself, he is suddenly struck by a bolt of lightning and the game ends.

The game includes two possible endings. The standard ending will happen if and when Dr. Jekyll reaches the church at the climax of the sixth level. Jekyll then marries Miss Millicent and presumably lives happily ever after. The alternative ending can occur only if Mr. Hyde reaches the church (which is usually not possible given that Hyde is struck by lightning if he progresses further than Jekyll; the exception is the second half of the final level). A boss monster named Letule will appear in the form of a floating head, and if successfully defeated, Hyde will transform back into Jekyll and can marry Millicent in an elongated wedding ceremony. The ending shows a bolt of lightning with a silhouette of Hyde and a cross behind him, seeming to indiciate that Dr. Jekyll's evil persona has been vanquished once and for all.
Gameplay
The game consists of six levels, but the ordering of the levels differs between the original Japanese and North American version of the game. The Japanese version includes the levels City, Park, Alley, Town, Cemetery and Street. However, the North American version removes the City level and instead duplicates the Cemetery level, leading to an order of Town, Cemetery, Alley, Park, Cemetery and Street. The character of Dr. Jekyll walks to the right, and can jump to avoid obstacles, and can also jab with his walking stick. However, this is a pointless gesture since the stick inflicts zero damage on all adversaries with the exception of angry bees. Therefore, most of the Jekyll gameplay comprises of jumping to avoid coming into contact with enemies, since defeating them is impossible.

As Mr. Hyde, the game auto-scrolls to the left and the level is mirrored backwards, as well as becoming a lot darker. Hyde can jump much higher than Jekyll, but more importantly can also punch and throw a special ball which the box art describes as a Psycho-Wave, and which can kill enemies at a distance. Gameplay here should consist of attacking and killing demons as quickly as possible to relieve the anger meter, so that Hyde may transform back into Jekyll. If the meter is not lowered quickly enough, or Hyde's life is depleted, he is struck by lightning and the game ends. If you move a further distance with Hyde than you did previously with Jekyll, it counts as Jekyll's evil side triumphing, meaning he is again struck by lightning and killed. You can also pick up coins occasionally as Hyde which killed enemies might drop. These coins then may be used by Jekyll to ward off certain citizens and avoid possible encounters. Dr. Jekyll and Mr. Hyde is a side-scrolling NES game loosely based on the original novel by Robert Louis Stevenson. Gameplay alternates between controlling Jekyll or Hyde, as they walk across town to reach Dr. Jekyll's wedding.