Unfortunately, this was a rather frustrating experience for me. More-so because the concept is right up my alley.
I don't have a delete key, so I was playing on hard mode for a bit, but got impatient while learning how to play without a way to remove a tile or restart a level.
So I peeked at the source (would be nice if it were linked here) and saw that there were gamepad bindings. But down, left, and right are all bound to d-pad down.
So I am playing with the gamepad next to my keyboard so I can occasionally press the north button.
The cursor could really use a preview of the tile being placed.
If I pick up a tile, move it left, and drop it, it would be nice if it ended up in the same orientation.
The Merger orientation is important, but its tile graphics give no indication of this.
I also spent a good long while thinking that it must be the distance between the emitter and the Halver that determined the phase of the halved beam rather than the orientation of the halver.
That said, at the end, I was wishing for more levels.