Fastest purchase of my life. It's more Brotato. It's more near-perfection. I'd also like to compliment the developers on their choice NOT to offer preorders, which is refreshing. That shows integrity and confidence.
I'll still be playing this 20 years from now. The base game sort of runs out of potential builds and content after 100-150h (which is still remarkably good value) but this DLC adds so much variety and new combinations that the sky seems the limit. It also gives previously-useless items, such as consumables when you have full health, a purpose. In fact, you can now make an entire build around picking up consumables at full health.
The new music in particular stands out in place of the mere 1-2 tracks that the base game has, meaning that I'm no longer replacing it with the Hotline Miami OST or Spotify. It's my sort of genre anyway.
The DLC was accompanied by the major V1.1 patch, which makes some balance changes that I frankly welcome, with knockback now more relevant instead of only being a factor in certain builds. The game's main weakness and a missed opportunity is still tutorialisation for a first time player - some of the finer things (such as damage calculation and *especially* the luck stat) still don't function how you'd expect them to function, especially when playing as more specialised 'tatos. The wiki is essential reading if you want to have success on higher difficulties.
I am genuinely surprised at the amount of negative reviews. They seem mostly to be from people who simply didn't understand the point of half of the mechanics from the original - you're supposed to adapt to what the shop offers you, and the increased RNG from the introduction of new items means that need to adapt is more of a thing. This is a DLC meant for players who have mastered the base game, so play it like one. Oh, and "it doesn't work because my computer setup is garbage" isn't a legit negative review, sort out your PC, that's your fault.