Multiverser

Multiverser is a tabletop multi-genre role-playing game, published by Valdron Inc., in which the player character is typically an alternate version of the player themselves. The player character travels to a new dimension every time they die. Each dimension is governed by rules called 'biases' which determine what actions are possible or not possible in any given dimension. The dimensions, more commonly called 'worlds', may feature any setting and plot the referee can think up from swords-and-sorcery to sci-fi.
Scriff.
When a new player begins a game for the first time, the referee describes an imagined scenario in which the player himself dies in some sort of accident typically involving electronics. From this event, the player character is inadvertently infused with "scriff". This fictional substance gets into player characters, with the result that death is not the end, but merely the perhaps painful step to the next world and the next adventure. The player begins the game controlling his alternate self in a new dimension just as he does every time his character dies. In this way, Multiverser uses death as a means of continuing the story, rather than ending it. The act of interdimensional travel, most typically upon death, as an effect of a scriff infusion is called "versing out". Any character who travels through dimensions in this manner, NPC or player-controlled, is called a "verser".
Biases.
Reality within individual dimensions is governed by four different "bias" categories: Body, Technology, Psionics, and Magic. Every skill has a score, or "bias level", organized under one of the four bias categories, and every world has a bias level in each of the bias categories. The interactions of these biases play multiple roles: modifiers on the chance of skill success, a limiter on what is possible in the current universe, a definition of what is known by the locals, a bonus or penalty to the chance to learn something new, et al. The four bias categories defined below.
The higher score of a particular world bias, the easier related tasks are. For example, in a universe with a high magic bias and a low technology bias (compared with modern-day Earth), players could expect to see a world similar to medieval Europe, but with wizards and dragons abound. A moderately high Technology bias, in conjunction with a slightly higher Psionic bias could put the character into a world very similar to the 2002 TV show "Firefly".
Worlds.
The book of referee's rules provides all the tools a referee needs to create complete Multiverser worlds. Nearly any sort of universe, ranging from almost normal to bizarre beyond imagining, can be modeled with the system, allowing referees great freedom in creating new places to take their players. This means that the worlds can feature original settings with unique stories, or the referees are free to choose to adapt a world from a favorite book or movie for their player to experience.
Books of Worlds.
While they aren't necessary for game-play, there are also two published Multiverser books with completed worlds with all the details required to be used in a campaign. Each book contains a total of 7 worlds. One world in each book is designed as a 'gather world'--a place with vast possibilities, where many players can be brought together and either work together or find their own goals and objectives independently. Also, one world in each book is a 'twin scenario' world which features two different universes whose similarities enable telling two very different settings in one description.
Skills.
Multiverser is designed to allow the player to attempt to take any action in and out of combat. The skills are categorized into the four bias areas tech, mag, psi, and bod, discussed above; just as each world has a bias level in each category, each skill has a certain bias level in its respective category. A mag skill with a high bias level, such as summoning a horde of guardian angels, would have odds stacked against success in a world without a high mag bias. Likewise, a moderate tech skill, such as operating a laser gun, might have a huge success rate in one tech-savvy world but would be near impossible in a low-tech dragons-and-deities world.
When a character attempts to perform a skill, the player rolls one standard percentile dice roll which determines whether the skill failed or succeeded as well as the amplitude of success. For instance, one roll would determine whether an attack connects and how much damage is dealt.
Reception.
Multiverser has been described as original and thought-provoking and has received acclaim for its ability to run multiple original campaigns in one game session. Reviewers have been impressed with the thoroughness of the rules and the diversity of the world books, going so far as to say that the books, particularly the books of worlds, could provide valuable information even for other gaming purposes. One reviewer contently cites the "Appendix 3: Basic Dicing Curves" in the rule book which explains the distribution of probabilities of various common dice rolls.
Critics have expressed disappointment with the complexity of the game mechanics, explaining that the depth and ubiquitous coverage causes the rules to be more cumbersome than many other tabletop RPGs; even reviewers who appreciate Multiverser's thoroughness explain that it comes with an unfortunate level of complexity. Some say that compounded with complexity is unclear, vague, or hard to follow explanations in some places. It has also been said that some rules laid out by the authors are unnecessary and take away from the potential quality of the game; a couple such cited rules is that the player character must be an alternate version of the player himself and that NagaWorld must be the first world a verser visits. The books do strongly suggest these two parameters, but they do state that they aren't definitive requirements—perhaps this misunderstanding stands as a testament to the complaint of ambiguity.