I've played this game on my laptop that has no dedicated gpu (only intel hd graphics 620) and noticed it lagged a lot in places with special effects, like those black star areas.
Lowering the resolution (all the way down to the minimum) fixed all performance issues for ne, and I'd argue the game looks better that way, because effects are scaled down to the same resolution as the pixel art and fits better altogether.
So if you're experiencing performance issues, give this a try!