The two I know of are Google's Blockly (https://developers.google.com/blockly/) and Microsoft's Touch Develop (https://www.touchdevelop.com/), which is more capable as a standalone app development platform.

I've tried writing a small program with each on my phone and quickly grew frustrated. It just isn't efficient for me. I much prefer the familiar ground of using Python on Termux using Hacker's Keyboard, and, even then, only to tackle trivial stuff that a calculator can't quite handle.

We build Construct 3, another web-based block programming editor, using a different approach which we think is more powerful and can make more sophisticated games. You can check it out at https://www.construct.net

Construct is targeted at professional game development market. It's not comparable with Scratch which targets the creative programming education. Construct is a full closed source proprietary premium payed ecosystem for professional game developers. Nothing to do with the open source, completely free and joyful nature of Scratch which delights the young creative minds of tommorrow (and today!). On top of that Scratch has an absolutely caring, loving and vibrant community.

Ashley, it may be too late now, but would it be a far fetched idea to make a Construct 4 with the engine in C++ or Rust or any language that can be compiled to WebAssembly, and make the web runtime with WebAssembly ? That would be the optimum way, of course harder then the current one. WebAssembly is shaping up pretty nice, i'm impressed. Or, another nice option would be to have native/web hybrid progressive web apps with WebAssembly running as exes in the machine, with lightweight exe sizes. Well , one can dream :)

The other day I was looking at the gallery and I found this "Complete XML Parser":

https://scratch.mit.edu/projects/780538/

LOL I want to hangout with that kid!