The game's major flaw (besides the repetitive item gathering) is the completely unnecessary use of the stylus. The controls in the game are stylus-only, when a regular control scheme would have been more appropriate. While switching among characters is easier with the stylus, moving Hammy and picking up items (which constitutes 98% of the gameplay) is awkward and detracts from the game overall.
An undiscerning child may have a bit of fun for awhile with Over the Hedge: Hammy Goes Nuts, and adults may even find the wacky, borderline creepy premise of the game slightly amusing. But if you care about children (or your own sanity), you may want to skip this one and just get the DVD instead.