Mine has to be Dragon Quest: Rocket Slime, a DS spin off of the Dragon Quest series that sees you playing as a slime operating a tank and rescuing the people from your town. You run around the overworld, collecting items to use as ammunition and saving money to upgrade your tank. The art and music are just as great as you’d expect from the Dragon Quest series. It made fantastic use of the DS’s dual screens. It’s also written for a younger audience, so a lot of it is just really silly and fun! Try it out for sure, I’m so sad there’s no sequel :(
Kenka Bancho. It’s a series of japanese games for the PSP, with only the 3rd game being officially translated and released outside Japan as Kenka Bancho Badass Rumble. It’s like playing a typical shonen anime set in high school, you’re a delinquent who fights everyone from the other schools in order to become the ultimate badass. It’s semi open world and you can beat pedestrians and innocent civilians, which reduce your badass meter, because real badasses only fight people who can fight back! And with their bare hands, weapons are for weak pussies! It’s over the top and fun as hell. I’ve only ever met one other person mention that game, and it was an RPG friend of mine, when he bought a PSP for himself.
Something I highly recommend for anyone that enjoyed River City Ransom or similar beat’em ups.