Playing the Steam version of
Tidalis, I stumbled upon the achievements of course.
One of which is "Chains of Chains Mk III": Clear 500 Blocks in a Single Chain. How are you supposed to do that? The board can be 12 blocks wide and 12 block high, which leads to a maximum of 144 blocks present at once. I can imagine that it's possible to clear 1,000 blocks in one
combo for "Combo Annihilator Mk III", but 500 blocks in one
chain?!
Seeing the collectibles' (non-)purpose in
Tidalis, I'm already thinking it might be similar with this... but un-achievable achievements would be just rude.