>>1529758MuvLuv Extra is a harem romcom.
MuvLuv Unlimited is a isekai harem romcom.
MuvLuv Alternative is a sci-fi mecha political war-drama.
MuvLuv Extra and MuvLuv Unlimited are part of the same disk released as "MuvLuv", but MuvLuv Alternaive was released separately 3 years later. They are part of the same story. Every MuvLuv game other then those three is just a spin-off.
The reason why there are two (three) games insted of just one, is because original author of MuvLuv, Koki Yoshimune, was told by his superiors that he wont be allowed to publish his first VN, unless it's going to be eroge romcom (which was the market standard back in the day). Extra and Unlimited are used as a setup for author's initial idea for the VN, which was realized in Alternative.
This why MuvLuv Alternative is twice as long as the original game and has a drastic shift in tone.
It's also the reason why most people who say "MuvLuv" actually mean MuvLuv Alternative rather then the original.
