Boulder Dash is a classic game that you will have to run into a DOS emulator if your computer is newer, as the game was built a long time ago. The graphics are pretty basic and look like the ones that you would have found in a game of the 1990s but this should not be a problem as we talk about a classic game.
The aim of the game is to collect diamonds and you will have to collect all of them that are in a certain level. In the upper area of the screen you will receive information about the number of remaining diamonds but also about the remaining available time.