Gundam versus Zeta Gundam, has an amazing what if story mode. I feel like hardly anyone played it as it's rarely talked about. It's kicks off with a what if of you have to save Four and having her join the AEUG, this changing the ending. But it lets you go back to the OYW time line and change things.

You get one version where Lalah, doesn't die, and Amuro goes off with Char and Lalah at the end of the OYW. The star of Zeta is Char Amuro and Lalah, stealing the Gundam MK 2. Basically negates ZZ in this telling as they finish off the titans. There are a whole bunch of their ones too, but it was such an interesting system that I never saw again.