Not surprised. Konami basically took a franchise with a cult following and added elements as if it was a marketing tick-box exercise. I can see how the conversation went in my head:
Manager: "What's in at the moment?"
Marketing guy: "Errr... well CoD added zombies a few years ago and they're doing well..."
Manager: "Brilliant, use assets from Metal Gear Solid 5, add zombies and we'll slap the Metal Gear name on for good measure! Instant profit!"
Dev: "Don't think the fans are gonna appreciate this one..."
Manager: "Shut up! Instant profit!"








