this is tough to answer, since the text input only provides feedback in the sense that it shows you what you've typed, and that's almost an accessibility issue (it punishes people who are not precise typers). I think I have to let people use their own judgement for cases which are not completely black or white, like this one.
Isn't pretty much everything an accessibility issue, then? After all, that the game only ever shows you one bit of information at a time is a huge accessibility problem.
The "precise typer" thing is more a difficulty than anything else, isn't it? Some people will of course find it harder to type without seeing the results than others. Plus, is there really a difference between you pressing the up arrow and you've got a character moving upwards, and you pressing the J key and a J appearing on screen? It's still a form of clear visual feedback on exactly what you pressed and what it did.
I think this gets more into the discussion of what exactly is input. If you consider the input here to be keystrokes then yes the text box is giving feedback, but if you consider the text box not part of the game, and the input to be the string passed from the text box to the game itself then it's fine.
Let's imagine a game where you have to type something in an arbitrary text file, then when you start the game (or press something or whatever) the game does stuff based on what text was in that file. I think this is very clearly not against the rules.
So you have an html page with a text entry, a frame, and a script that takes input from the text entry and draws one of the two colours on the frame. Is the "game" here the entire webpage or just the script? Is the text entry a part of the game, or just a part of the webpage external to the game? As long as the script doesn't affect the text entry in anyway, it's only form of output follows the rules of the jam.
"Where do the input, output and player end or start?" I love when games turn filosophical.
I think the input is kind of a help too. Because you see if you typed wrong or correctly. That's why I've removed it and worked in a different idea.
I understand that not 'precise typers' will get lost if they think they typed the answer correctly. Should we help them? or not.