Quantum of Solice showed strong legs at xmas, benefitting alot from Christmas shoppers buying it for just brand name. Bloodstone will inevitalby have a few more strong weeks once the holiday rush comes in, it still won't do brilliant but for the mediocre game it is it'll be fine. Can hardly expect or want a crap game to sell millions of copies.
Namco adjust Enslaved expected sales from 1m to 800k (Based on current retail performance) recently so I don't think it's doing as bad as perhaps some people want to suggest. Price cuts could hurt it though, it's hard to tell how retail took to the game - either way I reckon they'll take a stab at a sequel and I reckon it'll be well poised to do decent numbers, similiar to how I expect Darksiders 2 to do alot better then the original.