In 5e, Otto's Irresistible Dance forces its target to do the following things:
The target begins a comic dance in place: shuffling, tapping its feet, and capering for the duration. ... A dancing creature must use all its movement to dance without leaving its space and has disadvantage on Dexterity saving throws and attack rolls.
The creature can choose to take an action to make a saving throw against this effect.
However, if the creature decides to do something else instead, can it? The text clearly implies that it can make attacks, but can it cast spells? If it is flying, does it fall? Shuffling, tapping your feet, and capering are all things you can do with just your legs, so does that mean its hands are free to move at will?
A strict reading of the text would suggest that, unlike the 3.5e version, which locks down all actions, the 5e version of the spell still allows essentially all actions. Is this true?