I managed to get the game working by launching the it directly with steam closed.
$ .steam/steam/SteamApps/common/Magical Diary/MagicalDiary.sh
[S_API FAIL] SteamAPI_Init() failed; SteamAPI_IsSteamRunning() failed.
[S_API FAIL] SteamAPI_Init() failed; unable to locate a running instance of Steam, or a local steamclient.dll.
If you try to launch it with steam opened, you will get the segfault.
$ .steam/steam/SteamApps/common/Magical\ Diary/MagicalDiary.sh
Fatal Python error: (pygame parachute) Segmentation Fault
I'm on 64 bit gentoo, in Xmonad.
The game crashes for me even when run directly outside of Steam. It's best to bring this up with the game developers and see what they say about the crash.
The game developers seem to have fixed this, it works fine now.
steamclient.dllx1 2013-02
When I try to load Magical Diary from steam I get a dialog box asking me either to play the game or launch with the software renderer. No matter which choice I pick, the Magical Diary splash screen appears briefly, and then disappears. The following is the steam console log when I try to run it:
I'm on 64 bit arch linux, in KDE.