Hybrid Heaven is a video game developed by Konami Computer Entertainment Osaka and released for the Nintendo 64 in 1999. This game is most notable for its peculiar mix of genres: it has aspects of both role-playing video games and action-adventure games. It is also one of the few Nintendo 64 titles to support a widescreen mode. Gameplay Hybrid Heaven takes many elements from standard 3-D action-adventure games, such as Tomb Raider. The player can move in any direction, jump, crawl, climb, and shoot. The player must solve puzzles by disabling electronic weapons or through skillful maneuvering. However, when battling a monster (called a "biological weapon" in Hybrid Heaven), the game switches to a completely different mode. The player is constrained to a small room and can no longer jump, crawl, or climb. The monster and the player move around for strategic position in the room. When they are close enough, and have built up enough energy, one or the other will decide to attack. At that point time freezes and a single round similar to a role-playing video game turn ensues: the attacker picks an attack from a list, the defender picks a defense, and the results are displayed. After the attack, both monster and player return to jockeying for position in real-time. The Vs. Battle Mode plays like a regular 3D fighting game but with some unique RPG elements. In addition to regular punching, kicking, and grappling attacks, energy can be saved up to five times to allow for combos, achieved by either the player editing their own during a fight (one move at a time), or by choosing preset or saved combos. The battle system of Hybrid Heaven has a strong emphasis on leveling up. Experience using an offense or a defense directly correlates with the player's statistical abilities when performing that move in the future, with separate statistics for each limb, the torso, and the head. A body part can become injured, which makes it harder to battle a monster. The game includes Rumble Pak and Expansion Pak support. Plot Players assume the role of Mr. Diaz, a synthetic human hybrid created by aliens. In the game's introduction, he turns on his masters when he kills a synthetic human intended to replace the President's bodyguard, Johnny Slater. Diaz finds himself in a massive underground installation created by the aliens under Manhattan. As the game progresses, it