This is rather handy, as “Rebellion” is a good place for a newcomer to the series to start. It is a standalone expansion, so for $40 you get an entire game you can install and play without having to have purchased the original or either of the previous expansions (“Entrenchment” and Diplomacy”).
“Rebellion” is the latest (and last) expansion to this franchise.
It is the very antithesis of a casual game – you can really spend weeks on a single game, if you wanted to. It's metascore of 87 is the equal of “Europa Universalis 2” and higher than “Shogun: Total War”.
The original “Sins of a Solar Empire” has achieved near-legendary status in the 4X community.