Dr. Doom - you are sitting with you feet dangling (no floor)
Hulk - I haven't been on it - but DH has MANY times - but yes, there's a floor. (Dueling dragons is a "dangling" one)
Dr Doom is ace! I was so scared, I nearly didn't go on it as I thought it was one of those rides where they take you up slowly and then leave you there for a bit before dropping you but it's not. I am so glad I went on it and definitely plan on doing it again next time (several times )