Portal 2 on PS3 was the only Valve game on console to be cross play and cross progressions with PC via logging into steam on your PS3 and you'd get steam achievements +
Best crossplay games: play with friends across platforms | TechRadar
Call of Duty: Advanced Warfare Available for PS3, PS4 Cross-buy – PlayStation.Blog
Sony PS4 vs PS3 | Trusted Reviews
Ffxiv cross play is awesome..PC, PS4 and PS3 all playing together. Almost like a LAN party! : r/ffxiv
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