| Marth said: amazon lists single SKUs while NPD combines multiplats. |
Of course 
But if you look at the exclusives (single SKUs), you'll also notice some big differences. Nintendo's huge sales in December are part of the explanation but I still think NPD's final list of best-selling 2018 games will still differ greatly from Amazon's. That's quite surprising that both PS4 and XB1 may be underrepresented on the Amazon rankings.
Amazon
1. Super Smash Bros. Ultimate (NS)
2. Red Dead Redemption 2 (PS4)
3. Super Mario Party (NS)
4. Marvel’s Spider-Man (PS4)
5. Mario Kart 8 Deluxe (NS)
6. Super Mario Odyssey (NS)
7. Pokemon: Let’s Go, Pikachu! (NS)
8. Call of Duty: Black Ops IIII (PS4)
9. God of War (PS4)
10. The Legend of Zelda: Breath of the Wild (NS)
NPD
1. Call of Duty: Black Ops IIII (PS4, XB1)
2. Red Dead Redemption II (PS4, XB1)
3. Far Cry 5 (PS4, XB1, PC)
4. Marvel's Spider-Man (PS4)
5. NBA 2K19 (PS4, XB1, Switch, PC)
6. God of War (PS4)
7. Monster Hunter: World (PS4, XB1, PC)
8. Madden NFL 19 (PS4, XB1)
9. Grand Theft Auto V (PS4, XB1, PC)
10. Call of Duty: WWII (PS4, XB1)
