We should really use SDR2 though, I don't know anyone who calls it Goodbye Despair.
On the other end of the spectrum I've never seen anyone refer to the first one as Dangan_Ronpa_Kibou_no_Gakuen_to_Zetsubou_no_Koukousei
I would support a reverse alias for 100 Line Rainbow, not the Japanese title as the primary name unless it proves to be more common. Video games are kind of an anomaly in our naming schemes. We tend to go with the original Japanese title for manga and anime, which is great because it gives a level of consistency. Video games on the other hand tend to go with the English (American) localized title with some inconsistences.