When Skyrim was done sucking down my spare and not-so-spare time, I tried some smaller downloadable games. First I played "Dungeon Defenders", a tower defense/RPG fusion. Next (well, at the same time), I played "Orcs Must Die," a case of truth in advertising that was . . . an RPG/Tower Defense Fusion.
Starting to see a trend?
In fact, Microsoft apparently did, they even had a Tower Defense discount/special on XBox. It appears that Tower Defense has become pretty popular and produced some good games lately, even if the genre has been around for awhile (such as "Trapt/Dark Illusion")
This made me wonder, just are these games popular? Why was I enjoying them? Why did these RPG-style fusions seem especially enjoyable and well-received? I mean, yes, Tower defense was and is popular, but these games seemed to reach something in me and other gamers that made us play for hours and speculate on new ways to immolate orcs (I recommend a spring trap that throws them back into Brimstone, by the way).
For you current and future game professionals, here's my analysis.