Play one game each with Octane and Backfire

Chase Tinkerer through the city

Ride the derelict boat in southern Chinatown

Perform a Venom Jump, then a Venom Dash on a single enemy

Keep the bridge together

Get the trains running again

Ride Rhino through the mall

Achieved the "Lord of Frenzied Flame" ending

Achieved the "Age of the Stars" ending

Acquired all legendary armaments

Acquired all legendary sorceries and incantations

Defeated Dragonlord Placidusax

Defeated Shardbearer Malenia