>>107082758
DDLC took 2 years and he was fighting the engine the whole time, essentially writing an engine inside a less capable engine. That is just how he trained himself to learn to program (through modding games like smash and stepmania). Sure you can train yourself to drive with your feet and pedal with your hands, doesn't make it wise.
Even so he ended up needing help from people in the industry who don't use ren'py for example with character design.

Anyhow the scope of the game is inherently limited and nothing visually interesting happens outside still images and the occasional gif. You can look at NotITG to get a sense of the realistic limits of using prebuilt engines for visual effects.