Thanks Richard and misslilo.
Yes - very much so. One plays continuously in a logical manner and then have to change direction to find the achievements.
It's usually double work for the achievements alone.
It helps when there is a list and some descriptions of achievements to look for.
Then I treat it as another puzzle but most of the time - I think it is padding in-of a game. An 8 hour logical game play is extended to 12.