This is a 128-page .pdf in full-sized pages, and may not mean much to most people, except to those who had read the FIGHTING FANTASY pick-a-paragraph adventure-books, initiated by (the British) Steve Jackson in the 1980s and 1990s. There were a few books with science-fiction settings, such as "Starship Traveller", and so STELLAR ADVENTURES has expanded rules resembling the ADVANCED FIGHTING FANTASY RPG already released. The game uses only six-sided dice.
Characters have the 3 characteristics resembling the character stats of the books: SKILL, STAMINA and LUCK. But psionic characters also get PSIONICS, and Robot characters get a TECH characteristic. In addition there is a list of 37 Special Skills: science-fiction abilities which add to your base SKILL stat. Players add SKILL to Special Skill, and any modifiers, and roll at or under that amount with 2d6 (double 1's is automatic success, double 6's automatic fumble). Combat is an exception, however: there is a roll-over mechanic for Combat where you must beat the total assets of the opposition. Optionally, the combat rules can be harmonized with the roll-under mechanism of skill-use. Weapon damage is figured with a 1d6 roll and look-up tables to convert the roll into an actual damage amount for that weapon (you can boost the roll to a "7+" under certain conditions).
In character creation, a list of Talents exists, and optionally, a list of Mutations. The game then covers the SF bases with lists for Weapons, Armour (British spellings, don'tcha know!), Cyberware, Equipment, then sections on Robots and Vehicles and different Modules available to customize them. Starships, starship Modules and starship combat are covered, and also the various psionic powers called Traditions. Aliens and alien Talents get their chapter. In the chapter on Director's Advice, star-system generation is covered (six-sided dice are dropped on a sheet of paper to give the position of stars in a star-sector, and the basic number of planets around them! The rules then elaborate for other, more unusual star-systems and drill down to planetary placement as well.) Some tables, character and vehicle sheets are at the end of the book.
The skills and talents are beautifully described to evoke tense SF action moments. I loved that, that got me going with some ideas. But one weakness is that most of the Weapons, Armour, Equipment and Module lists are out of alphabetical order (except for the ordered list of Alien Talents). It may make for a mad scramble if players have to look up information in a pinch. Maybe you have to set up electronic index-cards for this stuff for a quicker look-up.
Some supplements have also been released, such as the ample Starship Catalogue adding many more starships, some .pdfs of printable stand-up Minis (figures), and a lengthy campaign called The Kaladarian Response.