Agree with above. Maybe they've updated their content more, but surgery was probably lacking the most in terms of clinical content on Firecracker. I tried to do that and any seemingly relevant medicine topics that I hadn't covered on my preceding IM rotation. Honored the rotation, but as above, I think I just felt comfortable on the shelf after doing practice questions (for Surgery I used pre-test) and 2 NBMEs, just since the surgery shelf was so random.