There is a LOT of stuff to go thru. At its most basic, it is fun space opera. Everything, including the kitchen sink!
http://en.wikipedia.org/wiki/Perry_Rhodan more describes the character and overall series overview (but see below).
http://www.perry-rhodan-usa.com/web1998/sersumm.htm gives you a summary of the first 1700 issues. As of this year they are in the 2500's issues.
In terms of playablility, you are likely not be the epic galaxy shaker. Perry and company are the heroes of the "epic" storyline, like Sheridan in B5 or Luke Skywalker in Star Wars. You may help the cause, but you probably won't make the galaxy turn when you turn. But its a large universe, so it won't be boring.
NOTE: Most of my knowledge is again from the American translation.
Perry Rhodan is a little hard to describe because each epic cycle can itself be its own campaign with its own tech and area to play in. The earliest take place close to home in local star systems, later ones I have yet not read/translated go to other galaxies. Some of the cycles have only the crew available to play as there is not really anyone else (one story had all of humanity genetically altered and dumbed down, except for the main characters). Others have the full blown empires of more or less equal level ready to snarl and conflict with each other.
On one level, you have have higher dimension beings trying to maniuplate the universe for their ends. More like vast group minds of previous mortal civilizations who have ownership/guardianship of clusters of galaxies. They use we mere mortals as agents for thier ends. The one for the Local Group is called IT (or ES in Germany).
Perry's big goal is for humanity to survive, prepare it and prove itself worthy of some goal IT has set 20,000 years in the future (maybe to add to the group mind?). The first books started in 1970AD (written in 1961, from a 1961 viewpoint), current books are placed around 5000AD or so, so he has another 15,000 years to get there.
The Traveller technology scale would have to be rewritten in all respects. Human starships are sperical, hundreds of meters or kilometers in diameter with weapons which slag planets with ease. I think we would call them mostly plama/fusion weapons. My favorite in the stories I read were Arkon bombs which fused lighter elements, then fusion again until the resulting planet is composed only of Iron and heavier elements.
Perry has a Mutant Corp composed of people born after nuclear testing with most mutants being looking like regular humans (double headed Ivan Goratchkin being the exception I know of) as a commando force. Most are clairvoyants, teleporters, telepaths and telekenetics with sprinklings of other powers.
Lots of Alien races (kinda). Many of the human looking races originate genetically from one source (humans too), but thru environment and other manipulation might not be compatible any more. Other races exist and are pretty strange, but the ones I read are "funny suits".
Lots and lots of Big Dumb object tech. In one situation, aliens called Akons had a force field enveloping their entire star system which prevented objects from coming in or out, even with FTL drives. In another story, entire stars formed a wormhole to another galaxy. Another empire, the Arkonide's, have an entire planet used as a factory to maintain its military. Their entire empire is run by one super computer taking up a whole planet, as the people are do detached to take responsibility for things.
:x :evil: thats HERESY :!: :!: :!: 
8) :lol: :shock:
