Hi dobsy. Thank you for playing our game and posting such thoughtful and very helpful questions! I shall do my best to address every issue you mentioned.
Difficulty of the puzzles: I agree with you. We may create 2 or 3 easy puzzles and re-order existing one in future updates.
"Free Drop" tutorial: Yes, it works. The aim is to teach players how to temporarily turn off "snap to tracks" by pressing left "Y" while dropping.
The round 3 way splitter: There is one inlet and two outlets. When marbles enter from the inlet, they go through the 2 outlets alternatively. We will mark them with arrows in next update.
Teleporting while you're holding a track piece: When you hold a piece, you enter Edit mode. Both joysticks' function change from teleport/turn to track editing. In Edit mode, it's better to "glide" with left joystick while holding A (horizontal) or B (vertical).
Sometimes it's hard to grab a piece: Yes, it's so annoying. I think we have found a way to improve the precision of Grab. This will be updated soon.
"Some pieces seemed to fit where it would be impossible in reality": In your opinion, is it a good thing or a bad thing?
Please let me know if you have other questions. Thanks again!
Lei