What I find works for most Linux games (and this) is to
1) Open the folder you downloaded the game in.
2) Right click (or you version's equivilant) and open up the properties for what would normally be the Executeable File (in this case it's the program labeled "Tamer - Public Build 0.0.4.1. Linux. x86_64" in the first folder.
3) Go to permissions, and "allow execute file as program"
4) double click your newly created executeable!
You can also download the Ichi.io app for Linux and it will do a fairly good job setting up games to run at a click of a button. You just gotta download games through the app, which isn't too big a deal IMHO. It even keeps the pages for the game together with the game itself, so you can quickly check back for surprise updates and stuff.