I agree with those saying it's pretty easy. Even on difficult, the computer frequently gives up the corners for no reason at all. I've beaten it every game I've played, and I'm not an expert.
The computer seems to have no sense of basic strategy -- i.e. what positions on the board are going to be most useful in the long-term. I assume that instead it is just looking ahead one or two moves.
This kind of strategy shouldn't be too hard to program in. Most importantly, strongly discorage any moves that allow the opponent to reach the corner. This means staying out of the squares surrounding the corners. Second, discorage moves that allow the opponent to reach the edge.
You don't have to look several moves ahead to be good in Othello. Just have a grasp of the *very* basic strategy.
Excellent little widget. Superb presentation, nice animation and a good, neat size: not so small as to be fiddly, but no bigger than it needs to be.
Only two negative comments:
1. The ghost showing the squares in which you can place pieces occasionally fails to show up.
2. The game is too easy. I can beat it just about every time even on the hardest skill level. At least one even harder skill setting would be useful.
Overall, though, an extremely nice widget.
Very nicely done, though sometimes the computer thinks indefinitely when only a few moves are possible. I took a picture of one such situation: