When playing astro‑maze, the delay is noticeable, and in a 2D action game such delays are especially apparent. Games that don’t rely on tight real‑time input might perform better. (I'm connecting from Europe, though.)

If you add support for drawing from images (such as spritesheets or tilesheets) in the future, and the client stores those images and sounds locally, the entire screen could be drawn from these assets, so no pixel data would need to be transferred, only commands like "draw tile 56 at position (x, y)."

(By the way, opening abstra.io in a German-language browser leads to https://www.abstra.io/deundefined which shows a 404 error.)

This method of multiplayer you propose is inferior in basically every way: you can't do client-side prediction to make inputs feel smoother, and non-trivial scenes will surely take up more bandwidth than just transmitting entity deltas.

Let me tell you that there is cheating in cloud rendering solution ( Stadia, AWS Luna ect ... )

So 100% there is cheating in your solution.

It's trivial to read the screen.

Sprite sheets are png with ztxt blocks with meta/frame info and a list of drawing operations to be done to construct vsprites based on any runtime server side operations done on the sprites.

There is limited client coding via popup Web view windows and a few js apis back to the client but nothing you can build too much off of.

(SS14 brings this model to an open source c# framework called The Robust Engine but has some limitations related to maintainer power tripping over who should be allowed to use their open source project.)

It was playable.

I wonder if you can use speculative execution to play the game a few frames ahead and then the client picks what to display based on user input, or something like that.

Each frame is 16ms, so you’d have to work ahead 6 frames to conquer the nominal latency of around 100ms, which may actually be 200ms round trip.

(In that case, something like Haskell would be a good candidate to build a DSL to build the decision tree to send to the JS client…)

https://github.com/skorotkiewicz/proximity-explorer

This doesn't work in 3D. Unless you have the server do the work of the GPU and compute occlusion, you'll end up sending data to the client that they shouldn't be able to have (e.g. location of players and other objects behind walls)

This is cool ... but I suspect just pushing video frames like Stadia etc did is just as efficient these days and a lot less complicated to implement and no special client really needed. Decent compression, and hardware decode on almost every machine, hardware encode possible on the server side, and excellent browser support.