Very, very good
Simple, neat, and very, very fun.
It is challenging, well thought-out, and quite addictive.
Built on simple, easy-to-understand rules and principles, there is no steep learning curve to overcome, and the score system eliminates frustration. If you're good, you get a really high score. If you're not, you still get a minimum score for each grid solved.
And, like the best of puzzlers, every level can be solved with enough thought put into it.
Very well done. Thanks for a great game.