Good job.
I have some suggestions for you that I think could help make this game better.
First is the flag placement command, I recommend having that available on the actual sweeper screen and not just the pre-loader. 60.4 KB can load awful quickly and I wound up missing it the first time because the game loaded so fast for me, and I never saw it. Second would to see if you can make it where the first click will not be a bomb, I had some awful luck and ran into quite a few games where I lost on the first click. 3rd would be to add some color, black and gray can be really boring colors to look at, and color helps to tell the difference between numbers, it's a nice to have detail.