By far one of the most enjoyable and addictive defense games I've played in a long time. I finished playing this a week or two ago, and just seeing the title here made me want to start it up again. IriySoft, the developers, basically transmute meh into awesome every time they lay their hands on the genre, so I wasn't particularly surprised. It's not as in-depth as, say, Gem Craft (which you should check out if you enjoyed this), but it does require a surprising amount of strategy for how simple it seems to be.
Happy to see the developers getting more love here!