I've seen people walk-through walls before, and people changing their walkspeed. I could just be seeing things, but I know the fundamentals to the game. Do you really think that I suck that hard at the game?
If the game's mechanics are the same as CS:S, the only way they can move through walls is if they're either lagging really bad or noclipping, and I can only assume it's neither. You probably just suck and are looking for a blank excuse. Changing speed can be achieved by using different weapons, such as a scout or a knife.
Is there that much of a difference between CS:GO and CS:S for me to consider purchasing it?