Mine Sweeper is available in two versions. The PC version has a larger game board in 4:3 format with more mines while the version for mobile devices has a smaller game board in portrait format with larger fields for fingers use.
To reveal a field (if you think that it doesn't contain a mine), highlight the magnifier button in the bottom left corner before touching the field. To place a flag on a field (to indicate the position of a mine), highlight the flag button in the bottom right corner instead.
This game requires a HMTL5 compatible web browser.
For some reason, it runs extremely slow on my computer (but only on my computer) when using Google Chrome.
If you face the same problem, try Firefox or Opera.