Dragon Quest Heroes: Rocket Slime 3 might have one of the cutest trailers I have ever seen. The series, which features a slime from the Dragon Quest games as protagonist, is filled with adorable and has the Rocket Slime fighting off enemies and going on adventures. The trailer is in Japanese, but you don't need to understand the language to appreciate how cute this looks.
Dragon Quest is a great series (even if I think of DBZ every time I play it), and I enjoyed the last Rocket Slime game I played, but there has been no American or European release date announced as of yet. Rocket Slime 3 will be hitting Japanese stores November 2.