This is where Eaglercraft shines. Because it is browser-based, many public "Eaglercraft servers" exist. To join:
No internet? No problem. As long as you have the HTML file saved locally, you can play singleplayer anywhere—on a plane, in a car, or at a remote cabin. eaglercraft 115 portable
Requires custom userscripts for optimal touch controls, though it can run on mobile browsers. This is where Eaglercraft shines
The search for " eaglercraft 115 portable " points to Eaglercraft 1.5.2 in a car
However, note that the render engine is not 100% perfect. Some advanced redstone clocks may tick slightly differently, and mods (like Forge or Optifine) are compatible. This is pure vanilla mechanics.
Even a portable game can encounter hiccups.