I'm sorry, but that argument is just ridiculous. This guy didn't rip off the IDEA--screenwriters and authors have been doing that ever since the first caveman scrawled a "rich girl, poor boy" story on a cave wall. This guy ripped off the actual characters, and even named the main character "pacman". Sure, the original game has been around for almost 30 years, but it isn't like Pac Man is some obscure work that no one remembers. Namco/Bandai currently makes a version for every platform out there--Android included.
As many people have said, all you have to do is create your own characters. You can have them running around doing the same thing Pac Man does all day long, it won't matter because they're YOUR characters. This guy did not even bother to do that. He used someone else characters and someone else's design. Hollywood does this all the time, because it ran out if ideas a long time ago. However, you won't see someone remaking "General Hospital" using the same characters, names, etc. even though "General Hospital" has been around a lot longer than Pac Man. That's because "General Hospital" never went away. Neither has Pac Man.
What it boils down to is this: creative people deserve to be compensated for good ideas. (They can be compensated for bad ones, too... if someone's willing to pay.) The idea may be simple. You may look at it and say "I could have come up with that!". But the fact is, you DIDN'T come up with it--and the person who DID is the one who deserves the recognition. That is the legitimate use of copyright law.
Maybe you aren't the creative type who can come up with something simple and iconic that's still making money 30 years from now, but just because you can't do it, don't knock those who can.