Pirates! Showdown

Pirates! Showdown is a casual naval real-time strategy game with one single resource (gold), two kinds of units (small pirate ships or big pirate ships) and only a few structures (towns, defense towers and obelisks). You start with a few towns, which generate a revenue stream. You can then spend your gold upgrading your structures (only 3 levels each) or launching ships in a straight line (which you do not control directly -- they automatically attack and capture structures along their way). Upgrading a town increases your gold intake rate; upgrading a defense tower increases its firing power; and upgrading an obelisk increases its influence radius (obelisks increase the firing power of any ships under its influence). Of course, your AI enemy is on the other side of the screen doing the same things, so you must be quick in your decisions in order to overcome it. Conquer an enemy town and you win the level.