It should be playable at least, I got 40-60fps on an old HP work laptop with i think Intel Iris integrated graphics with 100% render scale and Low shadows.
I do recommend the downloadable version in that case cause the web version overhead won't help performance.
You might also have to lower render scale (which makes the game a bit more pixelated but legible and playable), and also disable shadows (altho I do recommend trying to keep shadows at least "Low" if possible cause it does add a lot to visuals).
If you do end up trying it and run into bad performance issues, let me know! I might be able to figure out some more graphics settings that might help it run on more lower-end systems.