If you haven't played the newest XCOM yet, now is a perfect time to do so with the Enemy Within package. For all the XCOM veterans out there, you'll find a solid amount of new activities to engage in, as well as an unprecedented amount of squad customization. In other words, this is now the definitive Enemy experience.
It's by no means Windows 8's killer app, but provided you have access to a Windows 8 device, you could do much worse than Spartan Assault.
Dusty Revenge is a solid effort by PDDesignStudio, but it lacks the polish to really be put into the pantheon of brawlers. The good news is there's tons of promise, the art style is gorgeous, and as a general rule, the technical systems are in place to really make things pop with a sequel. With a little more polish, Dusty Revenge would be a pretty decent recommendation, but until then, only the hardiest of brawler fans need to apply.