I have noticed that too, but also that even the level "Hard" sometimes makes very strange blunders. Here's a game I played against the Hard-level with white. I had just checked with Queen on a2:
98. Qa2+
The computer, as black, now played 98. ... Ke3?? to which I could make the mate with 99. Qe2#. How can the Hard-level do something like this?
I guess it's great that it is capable of "human-like" blunders, but this?
Perhaps this is merely my computer acting up, but it seems as though "Little Chess Partner" is a sore loser. When presented with a unwinnable situation that will result in checkmate, he displays a never ending "Computer Thinking" message, and refuses to play the penultimate move.