I think the ideal limit as far as complexity with no manual coding would be something like this new marketing site for my game (warning: 100mb of video on Chrome): https://redo--fallofanempire.netlify.app/
Cursor with Gemini 3. I didn't manually write a single line for it (except for the actual wording). Gemini did the React stuff, styling, writing ffmpeg commands for re-encoding the videos to work better with scroll-based scrubbing, splitting them out into AVIF image sequences for mobile, etc. I use Cursor + Codex for the actual game as well but it involves a lot of manual work - even with a really modular system like Unreal it gets convoluted.
I tried doing a spreadsheet application heavily using Sonnet 4 (https://app.embedsheet.ai/) and found it would make a ton of mistakes and massive files that it would then be unable to reason with, I think if I did it again I'd do all the core stuff by hand.
Why not? With that kind of overhead from the assets an extra 200kb of JS is only going to make a minute difference in terms of load speed. It uses a lot of animation stuff that is provided by React libraries (Framer Motion, WebGL normal-based relighting, ThreeJS particles) that would need to be done separately otherwise and the component structure helps keep it organised.
Cursor with Gemini 3. I didn't manually write a single line for it (except for the actual wording). Gemini did the React stuff, styling, writing ffmpeg commands for re-encoding the videos to work better with scroll-based scrubbing, splitting them out into AVIF image sequences for mobile, etc. I use Cursor + Codex for the actual game as well but it involves a lot of manual work - even with a really modular system like Unreal it gets convoluted.
I tried doing a spreadsheet application heavily using Sonnet 4 (https://app.embedsheet.ai/) and found it would make a ton of mistakes and massive files that it would then be unable to reason with, I think if I did it again I'd do all the core stuff by hand.