head to head
Assassin's Creed Brotherhood asks more than Grand Theft Auto: San Andreas, and the gap is reads.

Optimization · Practiced Mastery
Ezio rebuilds the Assassin order in Rome, with a cult-classic mind-game multiplayer attached.

Optimization · Practiced Mastery
A sprawling open-world crime epic with RPG-style character stats across a whole state.
Assassin's Creed Brotherhood leans Optimization (Practiced Mastery); Grand Theft Auto: San Andreas leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Assassin's Creed Brotherhood
Kill-streak combat is stylish but easy
Grand Theft Auto: San Andreas
Flying school and drive-bys need decent hands
Assassin's Creed Brotherhood leans clearly harder on reads.
Assassin's Creed Brotherhood
Hide-and-hunt multiplayer ran on human mind-games
Grand Theft Auto: San Andreas
Gang AI is scripted, never adaptive
Grand Theft Auto: San Andreas leans a little harder on variance, though the gap is small.
Assassin's Creed Brotherhood
Fixed campaign content
Grand Theft Auto: San Andreas
Territory wars and traffic add light randomness
Grand Theft Auto: San Andreas leans a little harder on optimization, though the gap is small.
Assassin's Creed Brotherhood
Recruit management and shop renovation economy
Grand Theft Auto: San Andreas
Stats, gym, weapon skill, and routes reward systematic play
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.