I haven't used Windows XP for years now, and I'm no longer sure what can run on WinXP, but if you have a web browser that supports moderately recent CSS (variables, flexbox, grid) and Javascript (local storage, speech API), that browser should be able to run a game made with this engine ( but I expect some of the CSS may need changes to be more compatible).
In 2022 only around 0.1% of all devices run winxp, that's a very small niche and I think that for anything other than retro gaming people should really switch to something else. I have currently no plans of making the engine more compatible for windows xp than it already is.