I really can not comment on what my settings are at present but I have a feeling it is set to hard (due to the fact I get fast spiders @ 3k), but from memory I think Centipede has a strange quirk where the game at advanced levels is actually easier if it is set to "hard" on the dips. The reason it gets easier at the higher difficulty is that the time for the segments that reach the bottom to reset to "slow" speed is less at the hard setting than easy.