Swell Foop is a puzzle game. The goal is to remove the objects in as few moves as possible. Similar objects that are adjacent to each other are removed as a group. The remaining objects then collapse to fill in the gaps and new groups are formed. You cannot remove single objects.
The board starts as a full grid of objects. Depending on the size of board you select, there are either three or four types of object. If a group of objects are adjacent and all the same type, then they can be removed simply by clicking them with the mouse (or by pressing the space bar). When you move the mouse over a group you can remove, the objects will start moving. The number of objects in the group, and the points you will score for removing that group, is shown in the lower left corner of the window. The more objects in the group, the more points you will score. Once the group has been removed the objects above them fall down to fill the space. If an entire column is cleared then the objects slide leftward to fill the gap.