Killzone 2, one of few major exclusives that Playstation 3 still holds, as sold 1.9 million copies since its release in February.

Halo 3: ODST, sold 2 million copies in a day...

For those involved in the ever-lasting debates or "console wars," there's not much defending that fact. Was it the brand name, the sheer number of X-Box 360s sold vs. Playstation 3 units, or was it the fact that Killzone 2 was missing one majorly important feature...

Killzone 2 was given a lot of praise for its graphics but it was limited in color palette which helped make the game's aesthetic become a bit of a bore just a few hours into gameplay. The main issue with the game however, is that the entire time you're playing with AI computer-controlled allies... but the game doesn't let you play with human friends through any sort of co-op feature. Why not?

That's a massive fail for any game that comes out nowadays to compete with A-List titles such as the Call of Duty, Halo or the Gears of War games. I can't for the life of me figure out why they wouldn't include such a necessary feature. Any game that features a proper splitscreen co-op system has my interest. Any "killer app" FPS that neglects that feature doesn't get much play time in comparison.

CoD has Nazi Zombies, Gears of War has Horde Mode, Halo now has Firefight and all of these franchise's latest installments include co-op play. You'd think the major exclusive PS3 title would at least have one basic co-op mode, right? Nope.

One of the best ways to enjoy modern gaming, is to sit beside my buds and work together in the latest video games. Unfortunately, so many developers are ignoring this feature for online-only play despite all the current-gen consoles allowing for four (or more) controllers. What a shame.

Are you a fan of local co-op play? Did that have a significant impact on sales for these games?

Source: Co-Optimus