You cannot permanently play as enemies (Nazis, Thugs, Animals) in LEGO Indiana Jones: The Original Adventures on Wii. The character roster unlocks heroes and allies only (Indy, Marion, Short Round, Sallah, etc.).
Specific puzzles let you possess or manipulate enemies for a few seconds:
Bottom Line: No villain campaign. But the possession mechanic is a clever puzzle twist—use it to reach secrets!