No longer hidden behind a beta of Steam, AI combat arena Gladiabots from GFX47 is now officially supported on Steam for Linux. Do note, the game is still in Early Access.
If you love strategy games and feel like you want a little more control over unit AI, this might be the game for you. In Gladiabots you assemble a team of robots, design their AI with a handy drag and drop interface and attempt to beat another AI in battle. There's decent tutorials, a campaign, cross-platform online play that doesn't require you to be online at the same time and it's really quite clever.
While the programming side of it is quite simple to look at, the features it offers can end up quite complex. It's a system that hides complication behind an easy to understand interface so as to not scare you away. It also offers up a sandbox mode, so you can toy with the AI as much as you want which is very cool. Once you've got the hang of it, there's even regular tournaments to get into too.
There's certainly an interesting learning curve to it though, the challenges can be a little difficult requiring some creative thinking. I've spent quite a lot of time testing, tinkering and attempting to beat it and it becomes a hard game to put down. Getting your AI to do exactly what you want, with a number of conditions feels insanely satisfying.
For a look behind the scenes at what the developer is planning to add and fix, they have a public trello tracker to follow.