This page in our trophy/achievement guide to Hitman 2 has the list of all achievements/trophies available in Himmelstein. They are part of the new content available in Hitman 2's new mode, Sniper Assassin - you can only use your sniper rifle. Himmelstein is the first mission available in this mode. The trophies/achievements can be unlocked in the titular mansion.
Trophy/achievement list in progress. We are planning on expanding the trophy/achievement list for the Sniper Assassin mode in the near future.
How to unlock: Get a score above 1,000,000 points on "The Last Yardbird".
How to unlock: Eliminate the three main targets with the cannon.
How to unlock: Sabotage the wedding.
Commentary: This trophy/achievement requires you to play alone - Agent 47 can't have any support. Check our walkthrough for "The Last Yardbird" mission.
How to unlock: Complete "The Last Yardbird" as Silent Assassin.
Commentary: To get the Silent Assassin rank, Agent 47 must remain undetected, kill only the mission targets and leave their corpses undiscovered.
How to unlock: Complete "The Last Yardbird" in Multiplayer.
Commentary: This trophy/achievement requires you to play with another player. You can play with someone from your friend list or with a player picked through matchmaking. You get this trophy regardless of how you have ended the mission and how much points you got.
How to unlock: Complete all "The Last Yardbird" Challenges.