Update: The brick removal and replanting features have been added! This will allow players to modify planted bricks, such as destroying bricks to allow new ones to be planted in it's place, and changing it's color. Destroyed bricks will still stick around for a few seconds as interactive physics objects, which you can push around and also repaint.
Here's a new video demonstrating these features:
All I have left to do is finish the animations and adjust the scale of the player, add a brick selection menu and make a few other changes, and the first playable demo will be ready to release!