You have dependencies in Windows too and often when you read about how someone cannot get a game to run on Windows, it is due to lacking something like a DirectX version or something.
Strange, I've never encountered that - GOG downloads, and Steam, seem to install whatever extra is needed with the game so they just run. I don't think I've ever had to manually install any extra stuff (or identify what was needed) with GOG or Steam on Windows. Whereas with the first three Linux games I tried, only one of them worked (and there were no errors or messages given for the other two). I guess that's what I mean by it seeming to be more work! But I understand that it may get simpler over time.
Well it's not really as complicated as it sounds - also, the additional dependencies required (for Ubuntu and Ubuntu-derived distros - it may differ when using other distros) are listed on the games' store pages. And as Themken pointed out, the same kind of issue occurs with Windows too, it's just the process around resolving it is slightly different.
I recommend considering Linux Mint - on Mint simply installing my common dependencies meta-package on a fresh install (after updating the system & installing/updating any graphics drivers as required) is enough for most games to work.
Ah, I see the difference between https://www.gog.com/game/kingdom_rush
in the Linux specs section. One has a scary list of files (the one that didn't work). It's a shame it is only on the store page - I don't see that when I go to purchased games and download an executable. Some of my games don't even have store pages any more, e.g. when a GOG game stops being sold, or gets a change of distributor, meaning that info might disappear.
I'm still not sure why - if the files are needed - they're not just added to the download, as happens with Windows games?
Mint was one of the three Linux versions I considered trying, but I got put off by the three versions. I couldn't find lists of which were best on what specs, and what the real differences were. I wanted to install Linux on more than one machine so just went for Zorin in the end because it looked most similar to Windows 7 and I could just get one install file on a bootable USB, rather than needing different ones for different computers.