the in-game cheats do work, but you have to play it on your keyboard and not the gamepad(no clue why it doesn't let you push f1 functions when using gamepad). as far as the achievements go, using the god mode will not disable it...so, go ahead and play it on god mode, but you have to play it on keyboard.
what if i enabled the cheats then i removed my KB & replugged my controller? will they still work?