An addition to Drake's guide: Gray parts will break in one slice. Brown, red or white parts will take two slices to break. Black or golden parts will take three slices to break. If you just slice like a maniac, the non-gray parts will stop you when you reach them, and you will have to wait untill you fall back to the ground. However, you can slice a part and then air-block, so you can fall back to the ground, jump again, and finish that block in one slice.