Along with kicking the visuals and audio up a notch with new sounds and a better interface, Desktop Tower Defense 1.5 includes several new (and expanded) challenge modes to twist your brain in a knot and/or induce frustration. New towers, such as the Boost unit that increases damage nearby towers dish out, helping you combat new enemies such as the morph and dark creeps. The game is also available in five languages, including English, Spanish, German, French and Italian.