Finally finished the game, including all the non-grind DLC content.
I've been taking it slow. I think these sorts of grindy Team Ninja games are best played in short bursts, like a few missions per day, that way they don't get repetitive and you come back the next day and everything feels fresh again. Also played without companions so some missions/bosses took a while.
Overall, really fun game. I enjoyed it a lot more than I thought I would.
I don't know how Team Ninja does it but despite their games feeling like budget indie titles with graphics from 15 years ago and tons of reused assets they consistently manage to make melee action combat systems that play and feel better than 99% of their competitors. Wo Long is the exception so far, but even that game I wouldn't say is bad and I enjoyed my time with its demo, it just wasn't as good as I hoped.
SoP's combat, while a bit simplified compared to Nioh, still posses enough depth to be interesting while also being very responsive, fast and fluid. I really liked the Soul Shield mechanic. I think it's one of the best "parry" systems in action games. It's extremely strong (completely stops most attacks and lets you throw some of them back at enemies) but you are punished severely for mistiming it. The problem is that it's so good that it completely invalidates the normal block move, but maybe I just didn't find a use for it. Other than that, there's a ton of weapon skills, a ton of classes each with unique abilities, spells etc. You can play pretty much how you want. I played the entire game switching to different classes in almost every mission until I settled with a few options (you kinda need to focus on a build or 2 in the DLCs).
Gear system is as autistic and pointless on NG difficulty as Nioh's, but I liked some things about it more. I liked the affinity system for gear, I think it's a very interesting take on set items. Basically, instead of items belonging to specific sets that give you more bonuses the more items you equip, every item now has a value that it contributes to 1-2 sets that exist in the game (there is one for every class). For example, the White Mage set at 400 affinity gives you the ability to ressurect after dying once per rest. If you equip 3 items that each give 133-134% White Mage affinity, you get the bonus. Doesn't matter what the items are. There is a lot of synergy between different sets and various class abilities that can be fun to explore. For example at 250, Berserker gives you a strong defense and magic resistance buff when you are near death. At 400, Dark Knight makes all "near death" effects active at all times. And that's just scratching the surface.
Speaking of bosses, I think this game has the strongest boss lineup in all of TN's games (at least those that I played) and one of the best in action games period. Almost every single boss does something unique and forces you to interact with the game's systems beyond just doing and receiving damage. For example, Chimera spams a gaze attack that silences you, preventing you from using most skills and spells and also has various heads that attack you independently that you can damage, temporarily disabling them; Tiamat constantly regenerates HP, forcing you to damage its endurance bar as opposed to HP; Elemental Core forces you to handle 2 strong ads of opposite elements, where you can steal spells from one of them and throw them at the other for a lot of endurance damage from elemental weakness bonus, etc. Almost every single boss has some sort of gimmick like this, which forces you to do something you've never done before, but at the same time none of the bosses are pure gimmick fights, where you have to do a specific sequence of actions in order to damage it. I enjoyed the boss fights in this game more than in Elden Ring, for example, where a lot of the bosses, while being very flashy and pretty just started blending together, as almost everything was either a small-medium sized humanoid that jumped around a lot and did 10 hit combos and the only gameplay was rolling until it stopped attacking and hitting it a few times, or a giant monster that usually involved standing under it and attacking its foot. None of the bosses in that game interacted with you in ways other than dealing direct damage, or applying a poison effect that dealt damage over time and there was no way to kill them other than just hitting them enough times.
SoP suffers a lot from being extremely low budget, there is a lot of repetition, the enemy variety is tiny (although recolors with new abilities help alleviate that), it doesn't look great and despite that it doesn't run perfectly (usually 120 FPS, but there were occasional slowdowns and drops to like 30 when spamming certain spells), the story is mostly nonsense (I understand what they were going for but some things are really poorly explained) even though Jack's dialogue is funny, but it really shines through where it counts.
Unfortunately, the DLCs were kinda ass. Much worse than Nioh's. The first DLC is the shittiest of them all. In terms of new content, all it adds is 2 bosses. No new levels, no new enemies, just 2 bosses in an arena room where the fight starts as soon as you begin the mission. And in order to unlock those bosses, you have to complete a certain number of existing levels with optional challenge modifiers enabled, until a bar fills up and then you can fight boss 1 and then repeat the process for boss 2. The second DLC I thought was the best one. It adds this game's version of Nioh's Abyss, but I liked this one more than in Nioh, it had a lot more going for it with various progression systems and the way levels were designed you were never sure what you are going to encounter. It also added this system where every basic enemy of the game could be promoted to a mini-boss variant with stagger immunity and actually new abilities. But again, no new content other than 2 bosses (although 1 of them had like 5 different variations). The last DLC is weird - it actually added a new map but once you beat it turns into a boss rush with outrageous difficulty. I should note, that like in Nioh every DLC unlocks a new difficulty setting, but unlike Nioh, each DLC in SoP MUST be played on the new difficulty associated with it, so I played the final DLC on the super hard CBT difficulty it came with and I've been neglecting my gear and build for so long, so my experience was similar to playing the DLCs in the original Nioh right after beating the game, so every boss took me like 4-5 hours to beat and I could count the number of their attacks that DIDN'T one shot me on one hand. I eventually reached a boss that truly was impossible for my undegeared character, so I grinded a bit, actually made a synergistic build and had a much easier time.
So all in all, very fun and underrated game. I'd love to see them do another FF game in this style, but seeing as this was a commercial failure, it's highly unlikely.
If any of you here enjoyed Nioh but are on the fence with this one, give it a shot. It's not as good, but still a lot of fun.