There's a trick that takes a bit more than a minute that shaves off more than 6. The moment you select solo, spam start to skip the tutorial, then again too retreat out of the first chapter. Go to the treasure hunt section in the top right, you should have a feather. Use it on the space 3 up from the bottom and the 2nd space from the left. This will give you 5000 hearts, and another feather, which you want to use on the space 3 more to the right of the previous space, which'll get you 1500 more hearts. You can now exit out and buy a weapon from the arms altar, as long as it is 5000 hearts or less. Then you can move out, but now, the game will let you set the intensity, which you'll want at 5.0. Because you get the gate the first time through, you don't have to run through the chapter again, saving about 6 minutes in practice.