Very fun

It's a modern take on a classic game and I like it. Very original.

pretty good

very nice concept on the minesweeper game!

Very Addictive

What you have is a brilliant concept, and graphically the game is pleasing.
The sound fx are ok, but the bleeping can be a bit irritating after a while- thanks for providing a mute button.

There is room for improvement- hence 9 and not 10;

Put the instructions screen at the start- before the 1st play.

Adjust the controls so the game is mouse only (Right click for flag, double click to reveal adjacent squares.)

Some music would be nice too.

If you really want to go all out; the score should increase with difficulty, and some temporary upgrades wont go amiss either (X-ray mouse let's you see mines, pause the scrolling, 2X points ect...).

Integrate this with the medal system and you'll be on the front page for weeks!

Suggestion

I like minesweeper, so this is kinda cool, however you might want to think about adding a main screen instead of just starting the game. I had no idea what was going on right away.