Call of Duty has earned a reputation for being a sales powerhouse in the industry. At this point it's so successful that it isn't often compared to other games, but rather itself. This has placed an incredible amount of pressure on Activision to sell tens of millions of copies in each subsequent release. While that isn't a problem when sales are hot, in the case of a down year it's enough to make hearts sink.

Speaking to CNBC, two separate sources shard after viewing NPD Group figures that Infinite Warfare fell well below expectations. The number going around is that the Call of Duty series has seen a 50% decrease in year over year sales.

This number is in-line with week one charts, especially a notable UK Chart-Track that showed a 43% dip during week one in the region.

Last year's Black Ops 3 was the best-selling title of 2015, currently recording over 20 million sales and the title of "top-selling current-gen game". It has only more recently been challenged by Blizzard's Overwatch.

With this in-mind, Infinite Warfare's downtrend is not good news, but doesn't necessarily mean that the game flopped. Even half of Black Ops 3's sales is more than 99% of games will ever achieve in their lifetime.

What is worrying is how far Activision went to prop up this year's Call of Duty. It invested more into marketing than last year, and also executed on what ended up being an abrasive but successful Deluxe Edition which included an exclusive copy of Call of Duty: Modern Warfare Remastered. This effectively brought in consumers who were very unlikely to have otherwise purchased Infinite Warfare, a tactic on a scale we've never seen before.

Infinite Warfare should sit around 12 to 15 million total units sold when all is said and done.