rank them purple coin missions!
I actually think that SMG1 had some better, more difficult and involving Purple Coin Challenges than SMG2. Those really tested your platforming skills as well as your nerves. Nonetheless, these were entertaining as well so I ranked them.
Purple Coin Flip 'n' Sprint- Just the way I like them: fast paced with precision movement required. And it also forces you to efficiently use the spins.
Tall Trunk's Purple Coin Slide- Same stuff. Requires a good strategy and flawless execution.
Luigi's Purple Coin Chaos - Maybe I like this one because this one is a breeze compared to the one in SMG1, but it's really fun. You still have to map out a path and execute it perfectly.
Purple Coin Beach Dash - Short, but very fun.
Purple Coin Shadow Vault- Actually, not that difficult. Just work your way outside-in. I even got hit 2 times and easily made it the first time.
Purple Coin Spin Speed Run - Pretty decent challenge as well. You really have to learn how to make jumps with the drill and use the gravity the right way in order to complete this one.
Purple Coins On the Rainbow Road - I think this one is fun as well, only a bit difficult since you do not have a lot of time. I dislike however that a few times you really have to hit the brakes to collect enough coins. It really slows the action.
Bulb Berry's Purple Coin Glow - Nothing special, just collect al the coins.
The Adventure of the Purple Coins - It's not that difficult, and requires a lot of concentration. It just wasn't really fun.