Probably OpenAL, yes. The error message I get (in a red-X dialog, immediately when I run "The Away Team.exe") reads
The code execution cannot proceed because OpenAL32.dll was not found. Reinstalling the program may fix this problem.
The only DLLs in the install directory are
sfml-audio-2.dll
sfml-graphics-2.dll
sfml-system-2.dll
sfml-window-2.dll