Hammerin Hero took me twelve hours to complete, which for some maybe a short trip, but considering this is a PSP game twelve hours of game time isn't bad. There's replay possibility in collecting the variety of Bento Boxes and unlocking the additional occupations and costumes.
The controls are fast, responsive, satisfying, and extremely rewarding to use. This platforming game has refreshing style and game play better than any PSP platforming game I have played. Enemies crash around the PSP's small screen wonderfully when you hit them.
Hammerin Hero is a hard game to defeat, it takes patience, timing, and skill to win at several points of the game, but this is a result of design rather than technical issues.