I found a couple of start paramter but i dont know what one of them does. Maybe someone can help me.

WINDOW start in window mode instead of fullscreen
OPENGL use opengl instead of directx
UNCAPPED disable frame cap
GODMODE receive no damage and deal 10k damage with every hit

SAFE what does safe actually do?

SAFE

Seems to skip the creation of the SDL window, and assigns the GL context without creating it.

I just tried the -godmode parameter and I died during the intro cutscene. (T_T)
Anyway, the code can mess up certain scripted events, like also Grandpa's duel with Fuge.