The Gun Sonata Add-on for Bulletstorm has 5 trophies - 1 bronze, 3 silver and 1 gold.
At the end of Guns of Stygia, kill all the enemies on the walkways before the explosions do
Kill a Burnout using the helicopter that arrives in Crash Site
Kill a Boss using the Hot Dog cart in the Hotel Elysium map
Kill 5 enemies at the same time using "Dung" in the Villa map
In the Sewer map Kill 5 enemies in 1 wave by setting them on fire then extinguishing them