There are a few visual novel-focused game engines out there. One is TyranoBuilder, which offers up easy game creation without needing to know how to code (though you can access JavaScript/TyranoScript if desired).

Nyu Media is hosting a game jam for developers who use TyranoBuilder. The TyranoBuilder Summer Game Jam 2018 is open from now until September 21, 2018! The theme of the jam is "when in Rome..." and only requires that games be built via TyranoBuilder.

Please note that only Windows, Mac and browser titles are allowed (no mobile versions will be reviewed). The TyranoBuilder Summer Game Jam 2018 also offers three cash prizes. The prizes are $500, $300 and $100 for first, second and third place respectively.