Giving players line of sight to the goal is also a good idea. The 'orient' button is intended to assist a player that got turned around. I would not expect an advanced player to use it very often. Don't require the user to hold it down. That allows them to use the 'help' button incorrectly.
It's good that you are attempting to use color to share information. You can also use shapes. Portal teaches the player that they can pick up anything that is shaped like a box, but spheres are deadly. Perhaps in your game all green objects can be picked up, and different shapes are used for different switches. Sticking to a single-color for objects the user can pick up would allow you to use other colors to teach players what they can and cannot use the beam gun on. Portal only lets the players use the gun on flat white surfaces, for example.
I would also suggest that for the demo puzzles you pick one highly specific aspect of the game's potential that you would like to display and make that the entire puzzle. A single puzzle at the end that combines many elements could also be effective, but the meaty puzzles that combine a small number of elements are the ones that you will build for a full game.
I don't fully grasp the mechanics that you've shown off, but here are a few ideas for single-concept puzzles:
-A puzzle that just requires the player to walk on the ceiling to the exit.
-A puzzle that is solved by swapping gravity to cause a block to fall to a location the player can use it from.
-A puzzle that requires the player to swap gravity while falling.
-A puzzle that requires the player to gravity use in one direction for an object and a different direction for themselves.
