The player is often fighting with the camera more often than the mutants and monsters.
Head-Switching could also get problematic in the heat of combat. The Dummy head is only good for socialising, and getting your plastic face punched in.
Glass Keys and Nuke Nuggets, both of them basically force you to go through the entire game again to find all required items, which quickly becomes a Guide Dang It!.
The mission "Sing'n'fishin' placards" has no hints, no checkpoints, and plenty of insta-kill traps.
