Having trouble getting Steam Terraria running in Linux

Still not working under Fedora? Hmm. Make sure you regedit .NET install key out of the right wineprefix. Using winetricks GUI, that means selecting the right radio button, if it isn't the default one. Also double check if it's the correct registry key you're editing out.

One problem I had with this (with nearly identical symptoms), was that I didn't keep close enough track of where all the stuff I was installing was going.

In particular, Winetricks installs (well did for me, anyway) Steam in its own wineprefix. I was installing my dependencies to the default one.

Once I fixed it (by adding

WINEPREFIX=<path-to-wineprefix>

to my commands), it all worked.

If it still doesn't work, make sure you have a version of Wine at least as new as 1.3.19.

There's a mono port of the engine called Linaria, have a look at that.