Disgaea 6 is pretty good, but a general downgrade for me.
I was personally a big fan of 5, I liked the space aesthetic even if Void Dark's army was a lacking in meaningful lieutenants(Suikoden 2 was like this, the northern country that was invading was pathetically small when you finally get to it in the end). 6's story is considerably weaker; I feel like if they translated "God of Destruction" to something like "Super-majin" it would have been easier to swallow, with how often every character says it. The face on the mob conveys this so they should've went with it. Regardless, the story structure is largely the same with 5 levels per chapter, 15 story chapters, more than a few are solid puzzles/challenges with geo panels that you can't just auto-pilot.
6's autopilot is great for a grinding game, and I love setting up a map and "baking" characters for reincarnation while I walk away to do a load of laundry or whatever. Programming the AI isn't particularly necessary, but it's very in-depth and fun to try, which is an incredible callback to Carnage Hearts on the PS1. This feature alone makes me feel like the game is worth the purchase, despite all my other reservations.
Disgaea's ridiculous numbers take another huge step in this game; level cap gets raised twice via Dark Assembly bills, first from 9,999 to 9,999,999 and then later to 99,999,999. Stats are likewise ridiculous and start in the thousands, and quickly climb into the quadrillions and quintillions. As such, there's the usual Carnage Dimension(both as an additional difficulty to the existing levels, and it's own 5-stage post game chapter itself), and now a difficulty further beyond that, the Rakshasa dimension(an indian type of demon people might recognize from La-Mulana 2, or Jake Alley). The autopilot/Demonic Intelligence feature makes these crazy difficulties feel very approachable, moreso than any previous game in my opinion.
Item World takes a noticeable step DOWN in quality, which is a shame. I replayed 5 recently, and the difference in quality between that version's Item World and 6's is like night and day. The core functionality is there; endless levels, farm innocents, hunt bonus rooms, alternate progression to the main game, etc. I guess I'll just hit bullet points as they come to mind:
- bonus list rewards on stage clears are largely HL/XP, with a heavy emphasis on consumables, and usually Diver/Filler items. It's pretty hard to get equipment, let alone rare equipment.
- enemy variety is a little drab since there are less classes/monster types(so there's less animation work, I suspect; this is as much a problem with the main game as the Item World)
- because of the main story's cut corners, there are far less interesting tilesets for the Item World to utilize. I would hope this could get patched, but I doubt it
- many stages have multiple Null geo symbols, and not enough colored geo symbols vs. geo tiles colored on the map to get a good Geo Chain going that does a satisfying full clear of the map/fills bonus gauge. Similarly, it's incredibly rare to find any maps where the Geo Panels are actually an obstacle or even a speed bump in the flow through item worlds. I've had about 500 floors done and have autopiloted all of them unless I see an Innocent I want dead or a bonus gate to grab, and have never been roadblocked by a Reverse Damage or No Melee/No Ranged road block. This may be attributed to the lack of a Sage-type geo focused class or related skills.
- I feel like there's less Bonus Room variety than 5, and 6 largely just copies 5's, down to the Item God tower of duplication(which now has a Prinny on top that gives you a choice of small, medium or large boxes, and I've only gotten extra Unique innocents from these). Bank Robbery, shopping centers, Professor & Clone rooms make a comeback.
- most maps are very small and short, and you can skip or clear a lot of rooms with just two good throws. You can rush rooms like in previous Disgaeas and don't need to do full clears of mobs to gain levels, which is ironic since the autopilot can be trusted to do this for you!
- It seems like it should be rarer but you will regularly run into a floor that is normal, but has an enormous amount of extra Lucky Board mobs, Level Sphere objects, chests, and 2-4 random innocents. I actually find these to be a nuisance though, because the innocents are frequently much lower quality than whatever you're farming. They're not outright harmful, but it's kind of annoying and an easy floor type in an already grossly easy Item World.
- The Innocent Town area after killing the 10th floor's Item General/King/God does NOT have the Innocents hanging around with silly lines anymore. Kind of an odd omission. You also don't get to "steer" the item with more bonus rooms, more likely invasions, more likely spheres, etc.
- No level fish is an improvement, I didn't like those mobs, but no Pirates/Invaders is sad.
- Item enhancement is done through a simple point system, no more passing bills through an assembly to gain movement/attack range etc. You just buy it outright. This point system also allows you to buy Innocents directly at interesting rates, or sell useless/extra ones back for points.
Ultimately I'd love to have the Demonic Intelligence system shoved into D5's Item World.
Music's about the same quality, voice-acting is above average with some interesting characters. UI is charming, the Dark Assembly is a cabaret now instead of a space war room, and voting is tracked with wine glasses instead of death stars, very cute. Etna is mega flat in 3D. Evilities feel a little dumbed down from 5 but there's still hundreds to customize from. D-Merit system is kinda nice but simplistic, not fully fleshed out imo. There's also no skill sharing/training anymore, so teaching heals and Espoir to various units is a lot tougher/happens later than most games, and weapon types no longer teach weapon-specific skills anymore; there's no difference between wielding a wand and a sword now, other than the base stats before you Item World the hell out of them, other than how some Evilities and resistances will benefit you. You might as well lean into spears, bows and guns even harder in general.
Looking forward to the Killia and Usalia DLC, but the current available characters are pretty good and I like throwing money at NIS to tell them I like what they make. You should to. I'd rate it a 6.5/10 but still strongly recommend for any existing fan to buy and play. It takes a lot of strange steps backwards in systems just to include 3D graphics, but the auto-play feature is so good I think it's worth any previous player's time to try. You get the same gameplay of previous games with the added variant playstyle of a hero manager/cookie clicker grinder.