Grand Theft Auto 4 (GTA 4)
yes as i've already said. the cheats ONLY BLOCK the achievement listed there and that is it. they don't block 100% they don't block anything else.
So once you get the achievement yes it still blocks it but it doesn't matter because you already got it.
same as GTA 3, Vice City, and San Andreas. in all cop missions you kill the person and anyone else that shoots at you.