This was guide was written and tested in OSX Yosemite. It most likely works with other versions as well.
1. Download and install Wine Bottler
http://winebottler.kronenberg.org/
2. Run Wine from your apps folder.
3. Add a prefix and save it. Now, you can close the Wine windows to get them out of your way.
4. Download Obsidian installer. Copy it to Users/You/Documents/Obsidian/drive_c (where you installed the prefix). I'll refer to this location as "drive_c" from now on.
5. Click the Wine glass icon in the upper right and choose “WineTricks”
6. Find dotnet20 (MS .NET 2.0), tick it, and hit Apply.
7. You’ll see “applying wine tricks” for a while, then the dotnet installer will pop up. Click next, accept the agreement, and wait for it to download.
8. Download obsidian installer, copy it to drive_c, and extract it there. Right-click obsidian40.exe in the extracted folder and choose “Open with -> Wine”
9. When prompted with “What would you like to do with it?” Choose the default, Run directly. Let the Obsidian installer use the default directory once the install runs (C:\games\Obsidian). Close installer when it's done.
10. Finally, locate games/Obsidian/Obsidian.exe within drive_c, right-click it, and open it with Wine.
Behold!
http://s27.postimg.org/xwz85lima/Screen ... _29_PM.jpg