Building: Movement - WASD / Arrows + Z
Erase / Place mode switch - E Place Block - Click
Change Block - Scroll Wheel / Click the Icon
Play Test / Build mode switch - Space
Playing: Movement - Arrows Run / Pick up Shell /
Throw Fireball - (Hold) Z Jump - X / Up Arrow
Play the Pipes level on the main menu and enter edit mode by clicking space to see how to use pipe transport.
What to do: You can make a level and share the code, or find a level code to play someone else's level, in the forum topic in Notes.
Don't complain about slightly long loading times. What would you prefer me do, make an empty game just so you can load it quickly?
So...here ya go.