You can really make any type of music with FL, but it's not the best tool for every type of job. FL is well-suited to dance, hip-hop, and other repetitive music, as it's workflow is based on creating patterns and putting them together, while creating automation to vary the sound.
You could make a film score with FL, but it would be like driving a "+" screw with a flat-head screwdriver. It works, but it's not optimal -- it's easier to do well a tool that's suited for the task (i.e., linear sequencers like Cubase, REAPER, Pro Tools, Logic).