As of this tweet: The game is available on Linux which I think means this game is TASable
probably.
https://twitter.com/lizardcube/status/1326952593457897472
The game has 5 major versions (latest one as of March 2023)
Pre-patched, Day 1 patch, September 2020 balance patch, Mr X Nightmare DLC patch and the 2023 balance patch.
Pre-patched is the version with the least exposure unless you were playing it on Xbox One or Windows Store when it first came out because those versions didn't get the day one patch at the same time as the other releases. It's notable for having SoR2 hit sound effects when playing as any kind of Retro character and the combo score mechanic is flawed for its super short duration (making it hard to get long Out of this World combos). Hacking a Switch/PS4 or using the Switch emulator is the easiest way to access the pre-patched build.
Day 1 patch:
This is the earliest version for PC Steam (windows users). This version is mostly identical to the pre-patched build but with a minor adjustment to Stage 4 just before the cops segment and Stage 3's 2D segment by removing 1 knife. This is the ideal build for pure speedruns as SoR3 Skate, SoR4 Blaze, SoR3 Shiva. The score combo mechanic got refined by giving the player a lot more time to waste between hits before it banks the score (making it easier to get long Out of this World combos). There is a bug/cap that prevents the combo score bonus going any higher after dishing out around 3000 points of damage.
September 2020 patch
This is the balance patch which gave a lot of buffs to SoR4 Axel, extra combo extensions to SoR4 Adam & SoR2 Max. SoR3 Skate and SoR3 Shiva got nerfed hard by reducing their OP Blitz attack from 64 down to 44 (Shiva)/40 (Skate). SoR4 Blaze has lost some infinites but some still work. Stage 12 is notably harder by buffing Ms.Y's mobility and giving her 100 more HP.
Despite being a slower version to beat the game fast, the score combo mechanic removed the cap meaning you can go as high as you want. 7500 points of damage is worth a whopping 88388 points
July 2021 patch.
This is known as Mr X's Nightmare DLC patch, added 4 new playable characters which are playable immediately after purchasing the DLC.
This build nerfed Blaze4's infinite combo loop that was used a lot against bosses in previous builds. Blaze2 has a single button infinite with her back attack, infact she was the biggest winner in the retro cast buffs. The SoR1 trio's police backup special got unintentionally nerfed by making the ring of fire into a line of fire, covering way less that usual.
Shiva4's best moves are the unlockable alternatives, especially his Spirit Palm offensive special, Max4 is really powerful with a jab combo infinite by a wall.
Estel was a bit underwhelming but has a charge attack infinite.
Skate3's alternative blitz is a single attack infinite that got heavily tweaked in a future update.
Adam4's air special both 1 and 2 have a bug where they can perform a gruntless version at 1HP when it's not meant to be possible.
Floyd's new air special increased his mobility by a huge margin.
Cherry's ground to air moves (except back attack) can no longer go over pits.
New colours were added to SoR4 characters meaning a playthrough with multiple of a specific SoR4 character is possible.
Mania plus got added but it wasn't a significant jump as the score targets to earn extra lives remained the same.
March 2023 patch.
The latest release and has a more challenging Mania+ difficulty run.
The SoR1 trio had their tools refined along with an introduction to a charge attack.
All retro characters can change colours meaning a playthrough with multiple of a specific retro character is possible.
Mania plus got tweaked big time by tweaking the enemy ai, increasing the score requirement for extra lives, introduced curse arcade machines and extra waves of enemy backup(s) were added during end of stage boss fights.
The Linux build was announced in September 2020 meaning that the earlier builds are probably impossible to use.
Personally I would use the latest version as it has the most challenging Mania Plus difficulty.