I fixed blurry images and low fps in the HTML build.
There is also an issue with zooming the browser before loading the level: [HTML5]: runtime bug · Issue #372 · coronalabs/corona · GitHub
It seems to be related to floating point or something (I only had problems when zooming at 67% and 33%, so the text scale value calculation is wrong.
You need to replace the webtemplate file.
Solar2D Folder → Resource → webtemplate.
Everything is still in testing phase (which worked fine for me).
If you encounter any other issues, feel free to let me know.
You can test it here: