At the beginning of the level are the Bob-omb Buddies, whom will give you access to the cannon right next to them, the cannon will allow you to go to higher places, such as clouds. Right after them you'll see a bridge, which the Goombas are guarding, and also a huge Chain Chomp that's guarding a star. All around are Bob-ombs that will blow up all over, and in the middle is a mountain with boulders coming down it. Koopa the Quick will also offer to race you to the top once King Bob-omb gets destroyed by you. The last level of Bob-omb Battlefield is where you have to beat the Chain Chomp you've seen in all the other levels. To beat it, one will have to ground-pound on its peg. Once the peg is totally in the ground, the Chain Chomp will be freed, and it will give you its star.
Big Bob-omb on the Summit. just go to the top of the mountain when you passed the chain chomp. battle the big bob-omb after.
Footrace with Koopa the Quick. go up to koopa the quick and he'll challenge you to a race. first one to the top wins.
Shoot to the Island in the Sky (Nintendo 64 version only). as it says just shoot there and hit the ! block.