I totally agree with you, I love Dark Cloud! It's the closest game to Zelda you will be able to find, and it even does some things better than Zelda. Restoring each town however you like is really funDark Cloud 2. This is an awesome game. I have yet to beat it though because of the final boss. But anyway...
Yeah, Dark Cloud 2 is kinda like OoT where you play two different characters who have to travel both from the present to the future (and back again) in order to restore certain points in history that the bad guy has destroyed (can't remember his name for the life of me). Also as they're restoring those points, they must find a way to travel to the past since that's there were the bad guy is.
It's also a RPG-like game. As for the rating of it, it's rated 'T'. It has a little bit of language in it, but other than that I think it's okay.
Also I would say that you could get the first game to this which is 'Dark Cloud', but of course I haven't played it myself but I really want to. I've heard that it's good.
Kidding. I was actually excited about this topic when I read the title. The whole non M rated thing definitely killed the buzz, though. Sadly, it leaves me with no suggestions. I'm positive MGS is a M rated series or I would definitely have suggested it as well along with God of War 1 and 2. Ah well...I totally agree with you, I love Dark Cloud! It's the closest game to Zelda you will be able to find, and it even does some things better than Zelda. Restoring each town however you like is really fun
Here are some other games I recommend:
-Metal Gear Solid 2
-Metal Gear Solid 3
-Kingdom Hearts 2
-God of War
-Grand Theft Auto 3
-Grand Theft Auto Vice City
-Grand Theft Auto San Andreas
-Shadow of the Colossus
-Timesplitters 2 (plays just like Goldeneye, and it's by the same developer team)
-Beyond Good and Evil (Love it)
-Legacy of Kain series
If you like music games:
-Frequency (Music game, by the makers of Guitar Hero/Rock Band)
-Amplitude (sequel to Frequency)
If you like fighting games:
-Marvel vs. Capcom 2 (if you could find it)
Edit: Oops, I missed the part when you said you can't play M rated game. So ignore GTA, Mafia, and God of War, and all the good games I listed