Currently the stacker terrain checks are done as follows:
After placing a brick, one pixel in front of the lemming and one pixel above the newly placed brick is checked for terrain. If terrain is found, then the stacker immediately turns around.
I see two inconsistencies here:
1) This behavior occurs even after placing the very last brick. As the pixel above the last brick is completely irrelevant for the stacker, the stacker should start shrugging and not turn around. Even more so as the terrain checks on last bricks are traditionally more lenient.
2) A platformer only turns around after placing a brick, that does not add any terrain pixel at all. So it is inconsistent, that the stacker turns around in anticipation of adding a brick that does not add terrain at one out of three pixels.
Suggestion: The stacker only turns after placing a brick, that does not add any terrain pixel (so there would be terrain checks for three instead of one pixel and all of them have to be satisfied).
Would support that suggestion.
This new stacker check would mostly break just ~ <10 replays (if any at all) and it is a good step to more consistancy. Rather change the stacker than the platformer + this way it makes more sense aswell :)
This makes sense. Note that there is leniency on the first brick (basically, even if the first brick doesn't change anything, the stacker is not turned away as a result); I definitely remember this being an intentional decision. It is possible some of the other issues result from implementing this poorly.