Simple question, can't get full screen due to the game 'not being able to switch to video mode'. The game works perfectly fine when windowed on any resolution. Do I have to set it to a lower resolution before attempting full screen or is it something else? No other problems just says it can't go to video mode.

Just got the game on steam, got owned by the AI, loving it to death.

I just want to full screen this beautiful game already

I've found that setting the resolution in options to match my monitor's optimum resolution worked for me, might work for you.
Cortex is a rather temperamental game.

Are you on a laptop or a desktop? What graphics card do you have, and what version of windows are you running? Is it 32-bit or 64-bit?

In any case, if it still isn't working after trying Duh102's advice, it's probably an issue with Optimus.