Very neat implementation of a classic, had a fun play-through. I like the visual shaking effect when you make a hit, it's a nice touch.
One thing I found a little confusing is the way the grid is drawn; at first I though the crosses where the middle of cells for some reason, rather than the corners. It's not very clear to me that the outer edge of the grid also contains cells; I'd perhaps add some more of those crosses around the edges to make it clearer, or maybe make it a full-fledged grid with fain, solid lines.
That's a lot of rambling on about a minor visual thing that bugged me a little. Overall, fun to play, well done.