These are also in general but if you're doing ILs I'm assuming you've got 100% unlocked already.

Keeping on the advanced reload mechanics allows for slam firing the lever action rifle and pump shotgun, which I do use in the run as it allows absurdly high DPS compared to basic reload where you can't slam fire. (Hold shoot and mash pump to fire rounds in the tube as fast as you can mash.)

Upgrade Greed first to go faster, then Sloth for the slower stamina drain. The virtues you get all this can be gotten in 1-1 through 1-4 and 2-1 through 2-4. The one on 4-4 can also be gotten with no down time, Pride for more max health or Gluttony for more consumables up to you.

Make sure to get the dash on 3-Boss it's faster.

ALL of the armors slow down your sprint speed, just wear the cloths.

Sell enough consumables to get 1000 gold that's all you need for the run.

Grab the quad launcher to ruin Xenon's day you can get it in the chest in 4-1 that's right at the start. Upgrade it for cluster bombs at the nearest upgrade table on your route. (I did it at Intermission IV you also probably don't need to grab the heavy machine gun in 5-4 like I did but old habits)

Get the XETA Rifle in 6-1 and get the grappling hook in the room behind it, this is extremely important for the rest of the run allowing you to break the rest of the maps wide open.

Grabbing the Whetstone increases your melee DPS this is especially noticeable against Grimaldia, The Demon Of Patience, get into the middle of his sprite like I do in the run and kill it in about 20 seconds.

The refight with Xenon use what rockets you have left, the redeemer under the stage and the laser for the best dps, the axe unfortunately doesn't melt him like it does Grimaldia.

Keep an eye on your oxygen during the epilogue!

It should technically be faster to destroy the artifacts but it doesn't really matter which ending you get.