Bulletstorm is frame rate limited to 62fps by default. This is where we became quite frustrated as the developer decided to encrypt the configuration files, making it difficult or at least time consuming to edit them. Using a simple polyalphabetic cipher the configuration files contain gibberish unless properly decrypted. There is a program getting around the net called "BulletStormINIeditor.exe" which can help you here.
Once decrypted it is possible to disable the mouse smoothing feature, which will uncap your frame rate. There are a number of settings within this file that can be changed to not only make the game run better, but also play better, such as FOV (Field of View) that can be increased to give the game a much better feel.