I'm not sure if you're calling River Raid the possible greatest Atari game ever... or River Raid Squadron. If it is Squadron, I thank you and I'm flattered; I'm pretty happy with it. If not, well, yeah, that's why I tinkered with it hoping some greatness might rub off on me. Either way, most of the credit goes to Carol Shaw. Personally, I might vote for a few others ahead of River Raid, but this is up there. I think a proper port of Gauntlet I and II to the Lynx could have been a major hit. If I had time, I would do that myself.
Aside from getting the 32-bit architecture working (which is built into flavors like Mint), I believe you shouldn't have trouble running this on Ubuntu 20.04 on the VCS. Let me know. You'll need to find an older controller though, or use a tool to fake it (or, if you are really ambitious, hack the Atari controller SDL2 info into the RRS binary -- something I might do myself).
As far as the VCS OS goes (if we ever get there), I'm guessing that 32-bit arch on it will not be attainable (unless I can maybe include the whole 32-bit env in the distro). I've been thinking about how to get this onto the VCS since I ported it, but haven't decided on a path yet. Don't want to buy GM:S 2 just for the 64-bit library. Might port it to yet another engine. Might finish the 7800 work (not looking likely) and wait for a VCS 7800 emu.
Yeah, I can't say I'm impressed with the VCS...... yet. I consider it to still be in early-access so I'm giving it a bit more time. Dual booting is fine, but I'm pretty disappointed we all can't sideload anything yet. Not just devs, everybody. I think everybody should be able to sideload a copy of River Raid Squadron if I build it for the VCS. I thought sideloading was a stated goal up front. We'll see.