As a rhythm game, I honestly think D4DJ is on par with the best offerings from the Bemani franchise. Its core mechanics are refined, intuitive, and kinetic, and its chart design is rock solid almost across the board.

At the same time, it leans so hard into being a serious rhythm game that it has neglected elements which could expose it to a wider audience. There are no 3D models or MVs of any sort, and while the original songs are fantastic, the soundtrack as a whole lacks any sort of cohesion or theming due to the sheer number of songs they've crammed into the game. And while this is obviously more subjective, I just don't find the scenario that exciting; I'm loath to directly compare the two games, but I've felt compelled to read every map conversation in Project Sekai, while I've ignored this element of D4DJ almost entirely. I think that's a telling enough anecdote. That said, the anime for D4DJ is legitimately pretty great and I would definitely recommend watching it before the game for context on the characters if nothing else.

Anyway, that's all immaterial to why the game has me hooked, which is its fantastic rhythm action gameplay. The base mechanics are designed for a touchscreen device in a way that facilitates fun, not anguish. Slides and scratches are responsive in a way that flicks in some other games simply aren't, and an immutable five lanes for tap notes ensures that charts remain easy to parse and reasonable to play with two fingers. Above all else, the chart design is simply top notch. The charters really know how to use the gimmicks available to them to draw out the rhythm of a song without just spamming as many notes as possible. It really feels like you're actually playing along with the music, something that a great many rhythm games have a surprising amount of difficulty realizing. Of particular note (heh) are the charts by Subatos; if you see him credited for a chart, you know you're getting an absolute banger, something that will really draw out the appeal of the song regardless of the difficulty level.

There are also a number of great QoL features that make it easier to focus on what matters, playing the game. You can customize basically every aspect of the playing field, not just note speed. Want the lanes to be wider? Sure. Want to alter the length of the playing field itself? Sure. You can even mess with more obscure facets of the play experience, like the exact opacity of upcoming notes during backspin segments. And while the fact that you have to pay a monthly subscription to access it is pretty questionable, I appreciate that there's a higher tier of judgment (Just Perfects, they have a 30ms window) available for players who really want to master the game and improve their timing. It comes with a fast/slow display during gameplay and on the results screen for good measure.

There might be better games on the market if you're primarily interested in the "anime girls" part (and I say that with love), but I can't recommend D4DJ enough if you want a polished, robust rhythm game experience that utilizes touchscreen input in engaging ways.

Disclaimer: I am F2P as far as gacha goes, though I do pay 500 yen a month for the monthly pass that allows access to the advanced judgment system and unlocks all of the songs. I have extremely good gacha luck in this game, though... I think I have a full set of 4 stars for every group at this point, in addition to one of the busted anniversary cards (apparently these are internally referred to as 7 stars, which is pretty hilarious), and I'm not really interested in extreme score grinding, so I don't have much to say about the RPG/gacha elements, sorry.

Also, for the curious, the game silently runs at 120hz on Android devices that support it, much like prsk.

I've been playing this game since it started (EN server) and i really love everything about it.
I'm a F2P player that never expended any real life currency on gacha games and, to this day i have every song currently available and at least 1 4☆ copy of every character on the game (except the newer ones).
Yes, the fact that is a gacha would be one of the main reasons of why some people don't even try to play the game
But i can assure you that if all you want is a fun rhythm game you should try this one

I've been playing since April 2022, and have logged in almost every single day.

I picked this game up because I found out it has an alternate "Technical" scoring system, in addition to the gacha-based scoring also found in games like Love Live! School Idol Festival, BanG Dream! Girls Band Party, and Project Sekai: Colorful Stage!. Some people are opposed to the idea of it being behind a paywall, I figure the reason it's paywalled is because otherwise nobody would spend money, I decided to take the fee.

I was pleasantly surprised by how well-designed this game is. Hold notes do not require releasing them at the exact moment, charts are genuinely designed around two-finger play, each chart has a radar detailing the chart's characteristics, and there's a wide variety of songs, from the obvious originals that have many different styles from the 9 featured units, to cover songs by the same units, and even non-cover songs from outside sources. I was quite surprised that this game features remixes of retro game songs.

I'll...also admit that I've saved up several times for the gacha. I tell myself that gacha is an inherently exploitative business model, but I couldn't stay away from Merm4id cards...

Story is so-so, I only read stories to get free gacha gems, other than M4's and the side:nova stories.

P.S. If you are that rare combination of "Is a Merm4id simp fan" and "likes shmups", please come see me.