The never-ending battle between Activision Blizzard (Nasdaq: ATVI) and Electronic Arts (Nasdaq: ERTS) is continuing, and this time EA is sending an offensive from its Battlefield series.

After watching Medal of Honor crash and burn last fall, executives are pinning hopes on Battlefield 3 to take down Activision's Call of Duty franchise. And the stakes have gotten awfully high after Black Ops generated $360 million of sales in its first 24 hours on the market.

Electronic Arts is countering with a $100 million ad campaign that looks a little like a desperation attempt to slay Goliath. And Activision is playing defense by keeping Call of Duty users entertained with new content packs until its next iteration is out.

Call of Duty: Black Ops has already added the First Strike content pack, which sold 1.4 million copies in 24 hours on Xbox LIVE, and yesterday Activision announced that the Escalation pack will hit Microsoft's (Nasdaq: MSFT) Xbox LIVE on May 3.

EA has an uphill battle in trying to topple the fastest-selling video game of all time, and it's running start is more like a warm-up jog. Battlefield: Bad Company 2 sold 2.3 million units sold in March 2010, but that doesn't come even close to Call of Duty.

How big of a bet is this for EA? In the last 12 months, EA has spent $724 million on sales and marketing, and a $100 million bet on Battlefield 3 is not chump change. Not only does EA have to worry about Call of Duty, but also games like Take-Two Interactive's (Nasdaq: TTWO) Red Dead Redemption, which will engage anyone who thinks war games are played out.

It's tough when your biggest rival has such a smashing success on its hands, but spending $100 million to topple a giant is a risky plan. Shareholders should cross their fingers that it pays off.

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