Sonny/Sonny2: RPG Last Stand 2: Shooter Gemcraft: Tower Defense Age of War: Strategy
If I had to rank them, I'd go Sonny, Gemcraft, Last Stand 2, and then Age of War. Gemcraft is arguably the best flash TD out there (I like the original better though, Chapter Zero was far too complicated for its own good), and Sonny 1/2 are generally regarded as the best flash RPGs as well. Last Stand 2... never understood how it got so popular, you shoot sideways at a horde of zombies, yay. And then age of war... that game just never did it for me.
I loved the Last Stand 2, because it was intense, realistic, and you makes you go,"Holy ****, did he just die that easily?". The problem is, Last Stand 2 is WAY to short. I never really like Sonny, I don't understand why it's so highly rated, it was kind of boring, the choices in class was limited, and the story line is messed up. Age of War was fun, but to me it felt like it was missing alot of things that doesn't make it perfect. Gem Craft was also very fun and the concept of mixing the gems to make them unique was SUPERB, but the enemies were a bit boring to me and was abit too complicated for first time players. In my preference, 1. Last Stand 2/Gem Craft 2. Age of War 3. Sonny.
gemcraft chapter zero, age of war gets boring when you get to future and you just go back and forth fighting, sonny 2 doesnt have enough skills since you can get to the bottom in like 15 mins, and last stand is good but it looks creepy and gross