I played Open Hexagon again this week and I think I get where you're coming from. OH generally has faster walls and a faster cursor with more permissive gaps, whereas Heptagon currently has a much slower cursor but tighter reaction times, so it feels like you are moving through mud when you go from the fast game to the slow one.
I've balanced the new level 6 to feel much more like an Open Hexagon level, and I've also adjusted some of the existing harder + hardest difficulty levels to be more OH-like (this update will be out in a few days). The challenge now will be finding the right balance for each level. I think the slow cursor is better for new players, and I want both slow and fast cursor levels in the game, but I also need the difference between levels to not be too jarring, as it is currently when you go from Open Hexagon to this game.
We are planning on adding more graphics options eventually. Not sure why your GPU would be spiking in the options menu, will look into it.
Not planning on changing the colour scheme, but the cursor is definitely too close to the shape (sometimes even overlapping it) on some levels, which we'll fix soon.