Course fella, you could always lower the difficulty if you struggle. It is though pretty hard to fail to get past a level in any COD game EVENTUALLY, as the artificial intelligence will recognise you are struggling, and it takes over. Either that or you eventually notice the tricky area and where to stand to avoid the worst of the firefight.
COD though has become almost a kids game
Borderlands deffo sounds a better prospect, I've just started playing Sleeping Dogs though.