The later levels have more interesting dynamics and challenges. Not only does it get much more challenging to simply get to the end, it becomes a bit of a puzzler as well. But I can certainly see how you wouldn't like it.
I'm not sure if the first few levels quite show the game off in to its best.
The one thing I'm a bit confused about is how to play it after I've bought it on multiple devices. I'd like to be able to play it on my iPhone and iPad.
I've installed it on 5 iOS devices on 3 different Nintendo IDs.
1 - Purchase the IAP on your main Apple ID. Setup a Nintendo ID and link your game to that ID. The Nintendo ID tracks and syncs your game progress as well as your IAP.
2 - On your second device, install the game. During the initial game setup, link it to your Nintendo ID. Since your linked NID has the IAP, the full game unlocks and your progress is sync'ed.
Additional steps to get this on your other family member's devices:
1 - if the family member's device is logged in to the app store with their own Apple ID, log out and log in with your ID that has already made the IAP. *Critical* step so that you're not charged $9.99 again.
2 - During the initial game setup, *skip* linking to Nintendo ID. Proceed to completing the tutorial and make avail the purchase option. Go ahead and make the purchase. This is a bit of a leap of faith as it'll look as if you're paying for it again. It will say that you already own it and will unlock it without paying again.
3 - Create another NID and link the game to it. That NID now has the IAP tied to it. Play through it a bit so that everything syncs up on your NID.
4 - Delete the game. Log out of the app store from your Apple ID, and log back in with the family member's original Apple ID. Install the game again with family member's ID.
5 - During the initial game setup, link the NID. The full game should be unlocked.
The purpose of this is to keep your individual game progress, and when the app gets updated, you don't need to log in with your Apple ID to get the update. I setup my kids' devices with this method earlier this week.
Have fun!