> It's not legal

Based on what? Afaik decompilation is a grey area and projects that enforce clean-room design do it to stay out of this grey area.

Copyright violation. If you write a book and I translate it to a different language you own the copyright on my translation. (except poetry which is artistic enough that it cannot be translated and so your version inspires me but I can't just translate it ). Decompilation doesn't have enough creative work to call it anything other than a translation.

I'm not a lawyer. I'm reasonably sure I'm right so the above is good enough for discussion, but if you need legal advice see a lawyer.

Actually you should look up the info there, you actually don’t which is what a lot of fansubs rely on, they mostly only will own your translation if they chose to formally translate and publish commercially a translation in that country. If they don’t, you can distribute your translation for free. There is a lot of variability on this per country too, with very interesting laws in greece and germany in particular.

> If you write a book and I translate it to a different language you own the copyright on my translation.

Not quite true. You and I both own the copyright to your translation. Neither of us can publish it without the other's permission.

This project compiles to identical binary to the original one. Distributing this source is the same as distributing the game in practice.