DarthVolod on 29 April 2013
The two big ones for me are...
Silent Hill : after the original trilogy it went from bad, to worse, to just plain awful.
Command & Conquer : After EA got their hands on it they ruined what was arguably the greatest RTS series of all time that popularized the genre alongside Warcraft, Age of Empires, and Starcraft.
More recently though ...
Assassin's Creed: Started off as a fairly entertaining stealth/action hybrid with plenty of room to grow and improve, but Ubisoft turned it into their annual cash cow with each entry being more bland than the last.
