With Chaos Emeralds, you needed to have a Random-ish object in order to 'collect' the emerald, else you could come back the next day for a chance to meet Shadow or Rouge for a chance to win the emerald in a simple quiz, OR, a third option, if you failed, you could track the thief down and buy the emerald from them.Once you had gotten your chosen girl to a set level (Girlfriend) you could take her on a date to a hotel for the night, where you had an interactive sex scene.
You then wake up in your room knowing only your name and that you are on a quest to date a Macro girl, or at least, to make a girl Macro.
In a short interactive cutscene, you are introduced first to Amy Rose, and then Tikal, who gives your first shot at chatting up a girl. You have a limited amount you can do in a day, as you get tired and need to rest, but you can chat up girls, take them on dates, but need to work and other things to build up your stats to give you a better chance with the girls (Who will often give very clear hints what stats they want to look for).
However, despite all these fixes, MSDS.1 hasn't gotten attention that the original had.
A hidden gallery of images in MSDS showed a test shot of 'MSDS 2', a sequel to the game. In conversation, Tempy has stated that MSDS would be bigger and feature a 'customizable' character that can move though the game's world.
If you gave the girl enough emeralds, it wasn't too hard to enter the Macro side of the game, where you had an interactive sex scene, like the hotel, but with the Macro version of the girl or guy.