The lighting isn't even that bad sans indirect illumination, which unreal only just got recently and Unity is losing due to Enlighten being shut down.
This reminds me of people comparing open source software with proprietary software on account of aesthetics - it's not the licensing model, or the game engine, it's the presence or absence of artists that makes the difference.
The visual fidelity of a game is a moot argument and the quality of assets is subjective.
Also this post is really about showing off an engine made in Rust, a "hack" so to speak. You are in Hacker News where people post (usually technical) things that others might find interesting - but not necessarily useful. Consider we get posts about people writing software for retro computers, just for the fun of it.