Sonic X, Ganbare Goemon Recommendations
Both involve a well known Videogame hero traversing into the human world, learning about how society works on top of fighting the videogame villain using THAT device every episode. For Goemon, it's Ohagi and Impact. For Sonic, it's the power ring.
Either way, both are enjoyable, but both also involve the hero sharing the protagonist role with the token 'Boy human' character, whether it's Goemon's 'Tsukasa', or Sonic's 'Chris Thorndyke'.
Both also end with climactic space battles in one way or another, but I'll leave that or you to watch and enjoy. :)