Have played the game lots over the last week or so. Played until the wee hours yesterday, and today I tried to start it again, but now nothing happens. Zilch. No popup window, no error message or anything, it's as if I didn't try to start the game (20 times).

Not much to go on I'm afraid, but any way to solve this? It worked perfectly fine yesterday.

Only unusual thing I can think about is that I died in the mines yesterday, so quit the game with the "Quit to desktop" option rather than first going to the title screen. Shouldn't matter I would think, but you never know.

edit: Tried to run it within terminal, which at least got me an error message. No idea what SDL 2.0.5 is, but do you know how I can fix this so the game will run again?

It is indeed Linux Mint, version 18.2, 64bit.

I've not done anything to the games folder, but did install a couple of OS updates. Generally restarting a linux system doesn't do anything, unlike the weirdness of Windows. But I tried it, and now the game runs. Very odd, but at least it rurns now, so whatever happened underneath that causes havoc seems to have reset itself.

From what I could gather Linux Mint has SDL 2.0.4, and when I tried to run the game from terminal after the system restart, I still got that "please update" message, but the game still runs. Looks like a royal pain to actually update it, so as long as the game runs, I am happy. Just hope it keeps working from now on :)

So then I can start up the game properly again, and have a crack at getting some animals. Hopefully that will get me a second wind as just watering and farming is getting a little stale. Fishing is awesome though, especially now at level 10 and I can get more treasure chests.

Great, congratulations that it started up again.

You're right, it would be a pain to update just sdl to 2.0.5 Usually I would advice against updating system libraries beyond what the distro itself is offering. It just will create more difficulties down the line.
I'm running Ubuntu 16.04 64bit, which should be the base of LinuxMint 18.

So, if the game runs again -- all be it with an older version of sdl -- just keep it that way. Very good. Have fun!