Great entry in a genre that's been done to death – Galaxy Dwellers Review

I've no doubt there are untold heaps of tower defense games for iOS that I haven't even heard of, but in a heavily saturated genre, Galaxy Dwellers holds up very well. As some have noted, it has similarities to Kingdom Rush. You build bases to deploy soldiers, and you can upgrade these bases to increase the number of soldiers. You also can have a "hero" on the battlefield, with substantial combat capability, and which provides benefits to other nearby units. Where things get rather unique is in the unit upgrade system. Each location for building a base also has one or more support building locations next to it (and in turn, these support building locations may be connected to more than one base location). Build a melee unit support next to a base, and that base's soldiers turn into melee type. Build ranged, and they become ranged. But if you build multiple support buildings, and mix and match their types, you can end up with some very different units. Three melee buildings will give a totally different result from, say, two melee buildings and one ranged. The support buildings themselves can also be upgraded up to three times, providing stat boosts for soldiers from the connected bases. There are three races to play, each with its own upgrade tree, and one tree of shared upgrades. The lack of in-app-purchases means the game is actually properly balanced, and doesn't depend on cajoling you into spending money. If you've got room in your life for another tower defense game, Galaxy Dwellers is definitely worth a look.
Review by davidbrit2 on Galaxy Dwellers.