Rocks'n'Diamonds

If there's an CE
(diggable/collectible, can move slow)
and you walk into it from behind you can't dig it!











Or try to collect an falling emerald from above
after you set your speed to
double speed movement.

This is by intention. You can never dig elements that are just moving from one tile position to another. (You *can* dig movable elements if they have just reached their destination position when moving from one tile position to the other, though. But this requires proper timing, and if you try to dig/collect a moving element from behind its moving direction, you are always one step behind, so this usually never works.)