After blowing the patriarch's attempt to destroy the fleet of worlds, and this means also after saving this fleet of worlds, the trio decides to lay down, and for that flees again to the Ringworld. Where also maybe they will continue with their search for Louis Wu, or maybe not.
Because, well, they seem to care little about him. Didn't this all start because he had disappeared? But still, they just seem to jump from one problem to another without much point. In the first game this wasn't as much of a problem, as it was short, and clearly a game to showcase the Known Universe.
But this time they attempted to make a real game. Or so they thought. First they decided to apply even more game logic to their puzzles. This happened already on the first, where you would keep solving puzzles without thinking, just because that was the “logical” way to solve the problem.
Of course, if you were to apply real world logic to them you would end asking yourself how the hell did you know that this all was going to work. But that's not the only problem. Somebody had the great idea of making the game longer also. Longer means “lots of identical screens one after another”. Ok, I got that the Ringworld was huge a long time ago, no need to make me run a maglev for five minutes to reach the next station.
And then they also added mazes… Hell, they are simple mazes, but so huge and meaningless that it feels like somebody is making fun of you.
Still, there are redeeming qualities on the game. Yes, really, I'm joking. It's just a bunch of simple puzzles, lots of awful attempts to make the game last longer and a bunch of plots never resolved or just forgotten, and to make this better it even has an open ending promising a game that, fortunately, never came.
What else to say? There are worse games, of course. But I'm sure you'll find better things to try before this one.