AlienTiles is a basic isometric tile game consisting of one player who must pick up a cup, flower pot, and a watch before four nasty aliens catch and hit him three times (see the screenshot above).
The player is represented by a little blue man with a red cap in the center of the screen. Three of the four orange aliens are visible in the screenshot, although one of them is mostly hidden behind the black and white column just to the right of the player.
Isometric tiles are the basis of many real-time strategy (RTS) games, war games, and simulations (e.g. Civilization II, Age of Empires, and SimCity variants), although the tiling of the game surface is usually hidden.
Isometric tiles give an artificial sense of depth, as if the player's viewpoint is somewhere up in the sky, looking down over the playing area. It's artificial since no perspective effects are applied: the tiles in the row 'nearest' the viewer are the same size and shape as the tiles in the most 'distant' row at the top of the screen. This is where the term 'isometric' comes from: an isometric projection is a 3D projection that doesn't correct for distance.