If I enjoyed Corporation Inc, Penguins Attack TD 2, Warfare 1917, Warfare 1944, Oiligarchy, Crush the Castle 2, but I found them too easy, what would you recommend I try next? Any suggestions would be appreciated.
Those games do require some strategy in order to complete each stage. But here are two of my favorite strategy games: Warlords 2 rise of demons and Warlords They are fun to play.
Have you tried age of war? If you turn that game on normal or high difficulty setting then it can be quite enjoyable.
I never understood Age of War. I couldn't figure out if it was just button mashing or I was doing something wrong. I like the music though. And I did like Tower of Doom, while it lasted.
The Protector series is fantastic fun, it's TD with a twist. The only downside to those games is that you might want to play your own music... (SFX and the 4 repetitive tracks will drive you mad.)