As you'd expect the main story stays the same but the things, which are new/different are all endings other than the true ending (the one adapted by the anime), the tips and the many messages you get onto your phone. The endings I have to say definetly pack a punch when it comes to the fact how different the story could have went and I must say I REALLY enjoyed playing the game for just those alone. The other "new" things are, as already mentioned, the tip system, which is kinda like a wiki for many different words with good explanations and the messages, which mostly don't really appear in the anime. You get them from different characters and you can often respond in different ways to get unique follow up mails. Those messages are also the key to getting some of the endings but most just contain interesting extra information. The VN also goes into way more detail when it comes to the scientific part of the story. The physical principles described are mostly spot on (in THEORY the time travel could work with some slight changes) so some extra points if you or your partner are into that. When I played it half a year ago I was once again fully immersed in the story, even though my first watch had "only" been 3 years before playing the VN. In my opinion I would say it's an even better experience than the anime. It is fully voiced with the original japanese voice actors and contains many good songs, which were partially used in the anime.

All in all I'd definetly reccomend you to go play it (especially since it has been so long for you). Also as a heads up if you decide to play it: I'd reccomend installing the "Committee of Zero" patch for the game, as it fixes up the translation, upgrades the visual quality and makes the text more readable.

Originally posted by der_SB:

As you'd expect the main story stays the same but the things, which are new/different are all endings other than the true ending (the one adapted by the anime), the tips and the many messages you get onto your phone. The endings I have to say definetly pack a punch when it comes to the fact how different the story could have went and I must say I REALLY enjoyed playing the game for just those alone. The other "new" things are, as already mentioned, the tip system, which is kinda like a wiki for many different words with good explanations and the messages, which mostly don't really appear in the anime. You get them from different characters and you can often respond in different ways to get unique follow up mails. Those messages are also the key to getting some of the endings but most just contain interesting extra information. The VN also goes into way more detail when it comes to the scientific part of the story. The physical principles described are mostly spot on (in THEORY the time travel could work with some slight changes) so some extra points if you or your partner are into that. When I played it half a year ago I was once again fully immersed in the story, even though my first watch had "only" been 3 years before playing the VN. In my opinion I would say it's an even better experience than the anime. It is fully voiced with the original japanese voice actors and contains many good songs, which were partially used in the anime.

All in all I'd definetly reccomend you to go play it (especially since it has been so long for you). Also as a heads up if you decide to play it: I'd reccomend installing the "Committee of Zero" patch for the game, as it fixes up the translation, upgrades the visual quality and makes the text more readable.

Thank you for the incredibly thoughtful and thorough response. c: This is incredibly helpful.