Halflife2 was written in python!? :O
No, it was written in C++, although it probably uses Python for scripting.
FlameDuck has some serious misconceptions about scripting languages I think. Modern games (the underlying engine, at least) are usually written in C++, and levels are scripted with something like Python. This does NOT mean the game was written in Python! That would be as ignorant as saying "This house must be made out of paint, because I can't see the wood!"