For anyone curious about the Chibi-Robo series, it's EFFECTIVELY a trilogy

>Chibi-Robo: Plug into Adventure
Has a Wii port (originally JP only but has translation). The differences are pretty minor so go with whichever version you prefer.
>Chibi-Robo: Park Patrol
DS. Like Zelda 2 and Mario 2 mixes things up a lot, becoming a strange pseudo-sim game where Chibi-Robo manages a park. Not a bad game but expect something different from the original. Try it for a bit, and if it really doesn't click feel free to skip.
>Chibi-Robo: Clean Sweep
Also DS. Takes the best elements of the previous two games and makes the true sequel to the original's story. Great story, best gameplay of the series, downright God game. Don't look up this game until you beat the original because it's a direct sequel and WILL contain spoilers.

The two games afterwards weren't made by the original team, and are bland slop unrelated to anything.