1. Does any game in the series have any promotional content, I.E. anything that's either only available for a limited time or more complicated to obtain than DLC (like special codes or bonuses for having save data from a different video game)? 2. Is there anything permanently missable in any game in the series, even rewards for beating the game in a specific manner? 3. Is the Retro Collection identical on all platforms, even including an in-game achievement system for the platforms that lack the infrastruc...

Very nice looking collection, hope we get more retro collections like this on Steam!

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Music in the menu is quiet, but in the game VERY LOUD. In addition, in the games themselves, the sound constantly makes noises or unpleasant breaks I do not know how to call it. It is very annoying to the ears. Please fix it.