Yoshi's "Break the Targets" stage can be hard or easy. It all depends on how well you can use Yoshi's egg toss (Up B). Here are the instructions.
1. Break target
1 to the left.
2. Jump up and break target 2.
3. Go to the right and smash attack through the wall to get target 3.
4. Now jump up the platforms to reach the solid platform with target 4. Break target 4.
5. From that platform, drop down to the left and go under the wall. Once Yoshi clears the wall, use his second jump and egg the fifth target.
6. Drop down to the low level and destroy target 6.
7. Double jump over to the left section of the stage. Now double jump upwards and egg targets 7 and 8.
8. Now stand near the edge left of target 9 and lightly throw an egg to break the target.
9. Jump back over to the part Yoshi started on and drop down to the solid platform that moves sideways. When the platform reaches its rightmost position, jump off to the right, use Yoshi's second jump and egg the final target.
Yoshi's "Board the Platforms" bonus stage isn't too bad, but there are some tricky parts, so listen up.
1. Jump up to
2. Jump up to the moving block (the orange things in the diagram) that moves in and out of the walls above platform 1. From the block jump on to platform 2.
3. Jump to the right and activate platforms 3, 4, and 5.
4. Now you will see a bunch of platforms that fall rapidly. They move in a counterclockwise cycle but the up part of the cycle is within the right wall. Anyways there is one platform you have to activate here. Wait until that platform appears and then jump and use ground pound (down B) to land on the platform. If you don't use ground pound then Yoshi won't fall fast enough to catch platform 6. Once you get on platform 6, quickly jump to the right or left. If you think you can make it, jump right straight on to platform 7. If not, then jump left to the stationary solid platform and then jump back over to platform 7. Return to the stationary platform. Watch out for the falling platforms when jumping because they can push Yoshi down to his doom.
5. To the left of the stationary platform there are a bunch of platforms that cycle through clockwisely, but the bottom part of the cycle is beyond the bottom boundary. There are two platforms you need to activate in here, so just jump from one platform to another (kind of like running on a treadmill) until you get two activated platforms. Try to use only Yoshi's single jump since it's easier to time.
6. Now jump to the far left on to the last platform.