The sliding effect is too much disorientating (Maybe you can put each square on the screen at the same time, just make them appear in a different part of the screen, starting from top left to bottom right)
It doesn't let me move on empty squares where there was a wall previously
Viewing post in Time? travel? puzzle comments
Here is an illustration:
AAAA AAAA
APAA AABA
AAAA AAAA
AAAA AAAA
Where A is Empty
B is Block
P is Player.
The player cannot move right because one step in the future of his right there is a block. Although in his right currently there is nothing. Since everytime the player moves in space, the player also moves one step in the future in time.