Featuring Linux support, Fantasy Strike is a fighting game that's quite streamlined giving more people an opportunity to enjoy it while still being difficult to master.
Developed by Sirlin Games, this includes David Sirlin who previously work on games such as Super Street Fighter II Turbo HD Remix so they know their stuff. It shows too, Fantasy Strike is a fighting game that not only looks good, it feels pretty darn good too.
Fantasy Strike was actually partially crowdfunded through their Patreon, as opposed to Kickstarter. Using Patreon gave them some obvious advantages, like people being able to support them over a much longer period and stop and start whenever they wanted to based on the progress being made (explained in more detail here).
If you want a full run-down on what makes Fantasy Strike different, the developer has a long post up to go over the various changes compared to other fighting games. In short: It's simpler to get into due to the controls, the UI is easy to understand, a full tutorial with extra instructional videos, a special throw-escape counter ability, easily watch or challenge friends to battle, a huge amount of work was put into the netcode for online play and so on.
With the big 1.0 launch, an entirely new game mode was added in called Boss Rush. It's a single-player mode, that sees you fight against eight CPU-controlled characters with increasing difficulty. As you progress the AI gets smarter and they also get some crazy powerups too. To keep it balanced, as you progress you also get to pick a powerup before each fight, so you essentially build up a deck of powers to fight increasingly challenging enemies.
In addition the AI as a whole was improved, gamepad support was improved, performance was boosted and a whole bunch of other smaller improvements and fixes arrived with it.
You can find it on Steam.