You really should a bit more research before posting. amazing reviews are only really needed for niche games that only appeal to the hardcore market. games like far cry have a huge market, just look at wild lands it has a 70 metracritic and has amazing sales. 81 is pretty damn good, and it probably won't drop below 80. ign review is looking good, and is the most important since metracritic is weighted.
Wild lands with MC of 90 would have sold way more. MC scores will always infuence sales as they should.