suomizeus

Currently testing it out, but seems like you already got a few responses about that.

"Crypt of the NecroDancer is an award-winning hardcore roguelike rhythm game. Move to the music and deliver beatdowns to the beat! Groove to the epic Danny Baranowsky soundtrack, or select songs from your own MP3 collection!" -the description of Crypt of the Necrodancer on Steam Store, having all reviews being overwhelmingly positive.

In this article, I'm simplifying things without using the DLC in the article.

What's Crypt of the Necrodancer?

Crypt of the Necrodancer, often shortened as "Necrodancer" or "cotnd", is a 2D hardcore roguelike rhythm game with pixel graphics. In the game, you have to move on the beat with optionally being able to choose from different soundtracks (Danny B, A_Rival, FamilyJules7X etc.) in randomly generated dungeons across 4 different zones meanwhile fighting monsters and bosses, collecting items and weapons and continuing onto the next levels as long as you reach the final boss. You also are able to play with different characters with different stories, when every one of them has different abilities, upgrades or downgrades, and some being harder than others. As you die in this game, you lose the process on the current run and have to start over. This game was fully released back in 2015 by Brace Yourself Games.

How is the gameplay?

In the rhythm of the music, you are available to do an action every beat. Those actions are e.g. moving, attacking, opening chests and alternative actions that are done with key combos (pressing two keys at the same time) such as planting a bomb, healing or using a spell. You cannot make an action too fast or too slow than the beat is. This will result in missing a beat, which will leave you out of making an action during that beat meanwhile monsters are still able to do their own action. Monsters have their own action system, having certain mobs just moving horizontally and vertically, some diagonally, some moving every second beat, and so on. Monsters also have different healths, attacks, and coin drops.
Coins are used in shops in order to buy items, such as weapons, armors, foods, spells, etc. Shops are found from every single level (except from the boss levels). You have a coin multiplier, which is earnt from killing enemies. Coin multiplier can rise up to 2x after killing an enemy and 3x after having 5 enemies killed. However, the coin multiplier can be lost for several factors. Those factors include missing a beat, taking damage or false key combos. For the best coin income, you should not miss any beat and avoid taking damage.
The game also has 4 different zones, and every zone has different enemies, structures, hazards and themes. Zone 1 has theme of a cave, zone 2 jungle-cave, zone 3 ice and fire, and zone 4 a dungeon. Every zone has 3 levels and 1 boss fight (+ final boss, depending on the character).
The first character you're starting with is Cadence. Cadence has no special abilities, upgrades or downgrades. She starts with 3 hearts and a dagger. Items can be found later on the run from chests, shops, monster drops, etc. Cadence doesn't have a normal boss fight in zone 4. This is usual with every character that is part of the story of the game. Instead, she fights against the Dead ringer and the Necrodancer after that. After beating all zones mode with Cadence, you're available to play with Melody, and she starts with 2 hearts and the Golden Lute. Melody isn't able to attack directly, but anything next to her tile will get damaged. Melody isn't able to pick up any weapons, and her damage is always just 1. Other items are available to obtain. After beating all zones mode with Melody, you're available to play with Aria. Aria starts with half of a heart and has a dagger. She can't pick up any weapons, and some items are restricted from appearing on Aria run. Aria will die instantly if she takes damage or misses a beat. However, obtaining certain items gives her protection from attacks and a new chance to live. The game also offers different characters with special abilities, such as Bolt with beats going twice as fast, Monk where you die from picking up coins, or Bard having ability to move his character any time he wants, not having to worry about beats.
The game also offers you to choose from 7 different soundtracks: Danny B, A_Rival, FamilyJules7X, Chipzel, Girlfriend Records, and Virt

How popular is the game?

Crypt of the Necrodancer is shared on 8 different platforms; Windows, OS X, Linux, iOS, PS4, PS Vita, Xbox One, and Nintendo switch. The game has total of over 17 000 reviews across all of those platforms, rated about 89% out of 100%. However, the game really isn't that popular in the gaming community, at least in my opinion.

DLCs

I said that I would simplify the things without using the DLCs as a part of the information. Why? The "Amplified DLC" brings up so much new content into this game. A new zone, new monsters, new items, new bosses, new characters, and the list goes on. There's nothing wrong with that, but I felt like a beginner should experience the game without the DLC first. The game also has Soundtrack DLCs, being able to purchase and install the soundtracks of the game. Also not a really popular DLC, "Extras" offers high-quality fan arts and mini-documentary

Should I get the game?

In my opinion, it depends. The game is challenging. And after beating the challenge, you feel really pleasured for clearing the challenge. If you are impatient and don't have the nerves for this game, I don't really recommend it. For comparison, it took me over 100 hours to clear all zones mode challenge with a certain character. If you like challenging rhythm or/and pixel games, I recommend this game. My current over 500-hour experience with this game has been really positive. You always have a challenge to play and new things to find. You can currently save 80% from purchasing Crypt of the Necrodancer from Steam for $2.99.

Yeah I planned not to buy this game

I probably should test out the game. Sounds fun.

Really empty guide, but fills the basics for completely new players. Kinda useful.