Just thinking I haven't made a shared creation in a while... not bad - but the canvas is a bit small for a non-interactive scene.
A bit silly that only the first two sets of tiles are unique - the remaining palettes are combinations of the previous tiles. May I suggest you have two palettes: mid-ground items (for blocks), and foreground items (for items like the ladder or torch that can logically appear on any block)? Pickaxe just deletes both mid- and fore-ground.
If you were feeling ambitious you could also add an overlay layer (like fore-fore-ground) for fog, flame, smoke/steam, type effects.
I did like the darkness/normal toggle.
Needs right-angled blocks (left and right handed, & upper and lower: so a set of four) like tile 52 and 53, but solid in either the upper or lower half. If you only did the lower half, this would let you do roofs, and slides, and all sorts of stuff. Upper half would be necessary to allow consistency.
Definitely needs more backgrounds: really there is only one background that you colour-shift. Why not have clear sky / windy day / sandstorm / snowstorm / rain / rainstorm / hail / lighting / night sky / sun on horizon / moon on horizon?!?
Did I enjoy it? Well yes, it satisfied my momentary urge to create something... but I don't think I'll do more than one - just no real depth to this scene creator.