Is it normal, that M&M VI eats 35% CPU usage on a i5 4570 3,2 GHz?

And... how can i change the screenresolution or switch between fullscreen and windowed mode?

Alt + Enter should swap between windowed and full screen.

I don't know about the CPU usage.

F4 is for switching fullscreen mode.

And yeah, it eats a lot of CPU usage, I think the fps is uncapped or something. I just put my PC into power saver mode when playing it lol.

7 and 8 don't have this problem because they use directX and vsync.