This is the only main series installment of Call of Duty not developed using Infinity Ward's IW engine. Instead it uses the Treyarch NGL engine. Although Treyarch NGL, like the IW Engine, used Id Tech 3 as a basis it is otherwise unrelated to Infinity Ward's engine. It's unknown why the engine was never used again. It's possible it was due to the poorer reception of CoD 3 relative to other titles in the series. Also possible is the massive acclaim of CoD 4 the following year (which used IW Engine 3.0) might have convinced Activision to go back to Infinity Ward's engine, though nothing has ever been confirmed. Add
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In the German version all swastikas were either removed or replaced with iron crosses. Add