While its not impossible that Mercury Steam or Konami could have paid for good reviews (as much as any other game studio or publisher could), it's MUCH more likely that its just 'home team advantage'. By this I mean they possibly scored the game higher due to pride in fellow europeans.
We saw this with LoS1 and MoF too. The trend seems to indicate its just that. On the other side of the fence (or ocean in this case), American reviews seem to be pretty diverse on the LoS games.
It's somewhat common to have some bias leech in no matter what is being reviewed in relation to where it's being reviewed. However, because not many european studios make games the favoritism is really blatant and obvious in these cases. They're just excited to see their region produce a 'big name' game.