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I would move this, but I think it's just best you make a post asking this in the 4th gen help thread. But the version differences include things like Pokemon differences (Vulpix in SS, Growlithe in HG, etc) and you can get Ho-oh in HG first, and Lugia in SS first. But you can still obtain them both in either game. Not much differences really. If you want more info, you can check Bulbapedia or ask in the help thread, like I've mentioned.