Retro RPG: Battlelords of the 23rd Century
Today I'm looking at the 3rd edition of Battlelords of the 23rd Century, released only a year after the 1st and 2nd editions, and with the 4th edition following a year later and 5th edition a year after that, it's set in the year 2279 where the players are mercenaries (called Battlelords in this setting) of one of 12 different and very interesting species.
It's sci-fi mercenaries, with an interesting amount of background.