Looking over the official site for the game, it looks like an alternate universe version of G Gen. The announced DLC includes X, Turn A, AGE, Reconguista, and Seed ASTRAY: Princess in the sky.
The rosters for the game are huge, to begin with, and it's actually really fun in the original games to start off with the proto Zaku/GM (Zani) in 0079 and slowly upgrade your unit up the tech tree, to match and even surpass the series units you fight against as you play through scenarios from a given series.
Cross Rays so far doesn't have that feel as most of the series, that I'm aware of, already have the tech in place, so you don't have the progression tree of fighting tanks and Zakus/GMs to start and get thrown against already proven designs.
Yes, you do have the titular heroes from the respective series to help, but playing as a semi purist, it's very difficult to shake off the missing RPG progression feel, especially if you wanted to have a completely custom created crew to start the game with.
Game allows for creating customized characters, and they use the Japanese horoscope (D.O.B. , blood type) to determine starting stats and starting ability, which is kinda fun, especially if you wanted to see what you would be like as a mobile suit or warship pilot/officer.
You start the game with a basic ship with a single hanger capable of holding 5 suits at a time, and enough characters to fully crew the ship, and field 2 teams of 4 characters. One based on the ship, and the other as a Raid group, not tied to the ship but acts independently outside.
The ship can be upgraded to hold 2 teams of 5, and the raid team can be maximized at 8.
It's been fun so far, just tempered by the fact that I'm more of a UC buff than the alternate universes.
I also ordered G Gen Genesis for my Vita and Super Robot Wars V in the meantime.