Due to its high value, counterfeit copies are common. To verify an authentic US copy, look for: Pokémon Platinum Review - Nintendo World Report
Pokémon Platinum introduced several refinements over its predecessors to create a more polished experience: Pokemon Platinum Version (US)
The regional Sinnoh Pokédex was expanded to 210 Pokémon, allowing players to catch many more species before the post-game. Due to its high value, counterfeit copies are common