The images you posted don't seem to be working.

I don't see why you would need an image editor with all these tools made in löve. If you want a free image editor with these features, I recommend paint.net.

I'm not sure what "retro glow" effect you're talking about, but i'm pretty sure that moonshine might have something you're looking for.

Different files do not necessarily mean different states. You can use different files for whatever you want, which in this case is different states. You can use the example keharriso wrote above for what you want.

You can do this with the console field in love.conf.

As far as I know, there's no easy way to write and run love2d games online.
What are your "complicated reasons"? Maybe we will be able to help you.

Your game looks really nice and I want to try it, but unfortunately I don't have an iOS device. It would be great if you could release it on other platforms.

Hello everyone! Here is a recreation I made of the card game "Set".
If you don't know how to play Set, you can read about it here.
It saves your progress automatically when you quit.

You can't really avoid using love.keypressed for something like this. Even if you want to use an "independent library", you will eventually have to use love's callback functions. You can call the library's functions from within the callbacks, and the logic will still be inside the library.

I don't see why you would need to check all of the keys. You can instead make a table with the keys you need to check, and iterate through that.