there is a story behind how DG2 came to be, quite a long read but interesting if you're into insight looks on video game industry.
• When a successful game is a failure - http://www.polygon.c...-grid-2-console-port
It's pretty sad how Defense Grid 1 was kind of a financial failure. I expected Hidden Path to be ultra-millionaires (or at least financially stable) by now because of how awesome Defense Grid is. I really hope DG2 gives them the financial success they need to keep making awesome games.