I notice some times, when I move the mouse yo the right, that the right edge of the screen flashes a frame of a normal window (minimize button close button ext...). I have no other windows open so it's not a window showing from underneath, It's as if the game thinks it's running in a window for a second.
I'm running at 640x480 on low GFX settings.
Also I'd like to mention that as many complain I get bad slowdowns on complex levels, and I believe it is all the special effects. It would be nice to have an option to use very low quality special effects for those of us that experience these slow downs.
Another issue may be all the calculations the game must make while all the towers are targetting and doing damage and what not. I hope you are working to clean up that code as much as possible and hopefully stream line it to help make the game run smoother, the game is simple enough that thier should be no reason it can't run smoothly even when things get super complex.
It would also be nice to be able to have allot more control over the individual settings that control GFX quality.
I would even welcome an option to turn off special effects all together (maybe switching to simple place holders) based on fps.
I realize the game is new and I'm sure your working on smoothing out the gameplay.