If you're seeing the error when trying to launch Batman: Arkham City , don't worry — this is a common issue, and it's usually easy to fix.

Here’s a clear, helpful text you can use (e.g., for a forum post, support ticket, or guide): Batman: Arkham City – "Steam-api.dll is missing" Error (Fix)

Here’s what you can do, in order from simplest to most thorough: Sometimes Steam just needs a fresh start. Close Steam completely (check the system tray), then reopen it. If that doesn't work, restart your computer. 2. Verify Game Files (Most Likely Fix) This is the #1 solution. Steam will check for missing or corrupted files and replace them automatically.

Let me know if that solves it for you!