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I've been making a lot of use of the Steam Link and Controller I bought last Christmas, working out how to get older DOSBox/MMF2/GameMaker games working on the big(ger) screen so I can play them in bed. The easiest method is to add a shortcut for the game to the Steam library via "add a non-Steam game", because the Overlay defaults the Controller to legacy X360 mode. And also you can set face buttons to keymaps.

So is OpenTyrian still the best option? Or are there better ports out now?

I guess I should mention I'm using Windows 10
OpenTyrian is the only sourceport I know of. I think that's probably because OpenTyrian was, from my understanding, based on the actual source-code of Tyrian, rather than based on reverse-engineering, making it a much faster process for them to port the game (which is a big deal for a game with as much stuff as Tyrian, a port based on reverse-engineering could've taken ages). I can't think of much of a point in making any other ports after something like that TBH, aside from possibly adding in support for Episode 5, which OpenTyrian still does not support IIRC.

(Not that Episode 5 was very good anyways, lol)