Well after Traverse Town, I went to Wonderland, then I went to the Coliseum. But I couldn't break the barrels in time so I gave up and went to the Jungle.
Now I've just completed the jungle bit and Sora said "Let's go back to Traverse Town" so I went back there and Yuffie said to go and see Leon in the Underground Cavern.

I went down to the water bit where it is and it said "currently not open" so I couldn't get in there.
Do I have to do the Coliseum bit first? Cos I really can't break all the barrels in the time limit I've tried so many times