In Barnyard, the gaming environment lets you explore two farms. You can walk around and interact with other Barnyard characters like Otis, the laid back cow whose interests consist of swimming in the pond and playing gopher golf; Ben, Otis father, who usually brings around a clipboard containing chores to track and occasionally keeps coyotes and raccoons in check with the use of his milk squirters; Peck the chicken, who has a fascination with flying and oftentimes solicit help from other animals to achieve flight; a bunch of cows who enjoy bike racing and at times ride the cars of the farmers for the fun of it. There is a mini game in which you take part in one of these cow's pranks, making fun of the mailman behind his back. You can also ride a bike and travel in between the farms and nearby areas. As additional fun, you can perform tricks while riding your bike just for the heck of it.
Other mini games featured include gopher golf, maneuvering Peck as he flies through the air, squirt gun action with the use of your udder against raccoons and coyotes which incorporates bullet-dodging-matrix effect and several others. The mini games aren't too challenging, however, they are quite entertaining to do. There's also an in game monetary system where you get gopher bucks by trading in prized tokens and food items that you obtain by accomplishing parlor game objectives. There is a gopher shop that takes in gopher bucks to purchase upgrades for your bike or other barn decorations.
Graphics-wise, the game environment is a 3D rendition of the Barnyard world and it's realistic enough with details such as animals blinking and smiling when you interact with them, the sky being filled with passing clouds and having a sense of day and night during the game indicated by the presentation of the sun, moon and stars in the sky. Even flowers and bushes shake when you tread among them.
Comparing the GameCube version from the Wii, there isn't much difference with the functionality of the controls. The Wii's motion based control, however, is just more fun to play with compared to a typical button pad control. You get to be more immersed in the game as you try sway and shake your controls to simulate the movement and action of your character in the game. The Wii also runs in a higher resolution as compared to the Gamecube making the game look cleaner, a bit more defined and pleasing to look at. Price-wise, there is a significant difference between the GameCube version and the Wii version as the Wii is priced $20 more than the GameCube.
With only slight improvements done for the Wii, one could hardly say it's worth paying $20 more. However, if you're not so bothered with spending an extra $20 and want to experience a more physically engaging gaming experience of Barnyard, then you should opt for the Wii version.