This is a Slitherlink puzzle, with a twist. All of the twos are given to you in this puzzle. That is, any unclued square cannot have exactly two segments of the loop surrounding it.
(Click for larger size)
Celebrating the blog’s second anniverary. For those who think this puzzle is boringly easy, try to see how few non-2 clues you need to solve it. The new rule is a tight constraint, so the minimum is probably pretty low.