Playing Lite: World Jumpers
In its role as a Generic and Universal system, GURPS facilitates multi-world campaigns, where the same characters may travel from a magical fantasy world one week to a gritty spacefaring setting the next. GURPS Lite lets you run this style of game by including the Jumper advantage. Characters with this ability can travel between parallel worlds without any special equipment or ritual.
In a world-jumping Lite campaign, characters will do well with broad competence. They should be built on 200 points, with most of these spent on attributes and skills. In addition to these points, everyone should get the 100-point Jumper advantage for free, allowing them to jump between worlds.
Because they will be moving from one reality to another, characters will not get much use out of social advantages like Wealth and Status. On the other hand, a broad array of Languages (or even Language Talent) may be worth the points.
Each character should focus on a particular niche and take as many skills as they can to fit that role. So, if one character is the scientist, they should take first a high IQ and then most or all of the Natural Science skills as well as possibly Electronics Operation, Engineer, Mathematics, Research, and Writing. Remember that skills listed with “/TL” must be learned at a specific Tech Level.
Worlds and Campaigns
In a world-jumping campaign, the GM needs to create not only adventures but entire worlds. This may seem daunting, but remember that you only need the details that will be important during the adventure. Look at the list of subjects at the end of GURPS Lite (p. 32) and jot down one or two things for each that could make for a fun detail in play.
The two main types of alternate worlds are echoes and parallels. Echoes are just like our Earth, only they exist at an earlier point in time. Echoes allow for the fun of time travel stories without the headaches of changing the past and creating paradoxes. Parallels have already been altered, and history has taken a different course. Highly divergent parallels may have variant physical laws that allow for magic or even superpowers.
At the beginning of the campaign, the GM should define a base Tech Level for the campaign. Characters are built at this TL, unless they take the Low Tech Level or High Tech Level traits. Skills are learned at particular TLs. Characters can attempt IQ-based skills at higher or lower TLs at a penalty: -5 per TL above yours, up to TL+3; or -1 for TL-1 and an extra -2 for each TL lower. If a TL skill is not based on IQ, it takes a flat -1 per TL difference in either direction.
Even when dealing with worlds at the same TL, jumpers may find equipment they are not familiar with. Until you’ve had eight hours of practice with an unfamiliar piece of equipment, you take a -2 penalty to all rolls with it. The GM may roll against your skill secretly to see if you are familiar with a similar enough model to ignore this penalty or just rule that you are automatically. At character creation, you are familiar with two models of equipment for every point you have in a TL skill. A lenient GM will let you declare these familiarities as you encounter models in play.
If this campaign appeals to you and you want to dig further into parallel world gaming, you must check out GURPS Infinite Worlds. In addition to describing an entire crossworld campaign setting, it provides a number of worked example parallels and a complete system for generating your own.
GURPS Alternate Earths and GURPS Alternate Earths 2 explore a number of parallels, including such alternate history tropes as “the South won the Civil War” and “Rome survives to the present” through to weirder alternates like “Tesla transforms the 20th century into a pulp utopia” and “Jesuit Japan forms one corner of a four-part Cold War in the paranoid cyberpunk future.”
The various tech books will give you countless gadgets to pepper your worlds from the Stone Age to the Space Age. And a number of issues of Pyramid have included support for world-hopping games.