If it is random, but even if I return and spend more than 300 coins I can not pass it
It's random. It's a 1/3 chance, it shouldn't be 300 coins. Try to save and load to retry all possibilities.
will you work on any new game also do you have a pateron
I might work on new games in the future if I make my own art / find an artist to collab with. And at least for now, since the art is not mine for this game I don't have a Patreon, you can contribute to the artists' patreons though. (:
how to pass the magic part of the dark tunnel
Look at walkthrough (: