Quite a few BF games are not for sale because the service they've used for online gaming is gone. Those titles are: Battlefield Vietnam, BF2, BF2142 and their expansions.
Many of us would love to see them coming back (remastered would be nice, but a reworked MP that would allow us to play them again would be nice, too).
BF1942 is using a different system for MP and, as odd, as it may sound, it can still be played online. Though, you will have to jump a few hurdles to make it work
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