Crypt of the NecroDancer is a delightful rhythm-based roguelike. I had a ton of fun with it, but I couldn't make it very far. The loop of constantly dying and restarting over a bit stronger kept me going for a good while and I'd recommend this original game to a wide range of players, from both the side of rhythm enthusiasts and roguelike fanatics. I had some issue with the controls and still had issues with the difficulty at the end, but these are minor flaws in face of the positive things I have to say about it.
After a tutorial explaining you about the core mechanics of the game - you can do things only when you follow the beats of the music - you're unleashed in a randomly generated multi-layered dungeon full of enemies, traps, and treasures. You move and use your abilities by correctly pressing keys following the rhythm of the music - fail and you lose your gold multiplier - and enemies do the same too. Most enemies are small puzzles. The blue slimes will wait two beats, then move horizontally, the skeletons wait one beat then pounce, the bigger enemies have trickier patterns, and you have to learn them all. This is what ultimately turned me off from the game; It's easy to get killed if you're not super careful, I'll bump into the same enemy twice, making the same mistake over and over, and die, as per roguelike standards.
You get gold and gems during your runs, gold is used to buy items of various uses - weapons with more damage and range, armors to reduce the damage you take, various spells and enchantments to protect you, a tool to dig through blocks, and bombs. The gems are used to upgrade your character, more or less. You spend them to either unlock permanent upgrades - more health, more gold multiplier - or to unlock new items to be available at the store. You have to spend all your diamonds after each run, so you can't really stockpile them to buy that one permanent upgrade you want, and the store unlocks - while neat - don't make you stronger directly. I still have to say that I enjoyed the amount of strategies you can make with different pieces of gear, I love the weapons with the longest range the most.
By default, the keyboard shortcuts were weird, things like UP+DOWN and other uncomfortable combinations to use bombs, spells and other actions - like tossing throwable weapons - but that was one configuration screen away. Otherwise, the music is good, but if you're like me and die a lot, you're going to hear the same one over and over. There's plenty of good roguelike fun in CotND, such as random events, angry shopkeepers and a special kill room you get brought to if you don't finish a level before the end of the song.
With plenty of content, good RPG elements mixed with the music genre in a brilliant way, Crypt of the NecroDancer is a really cool game. Too difficulty for me - without any end to my woes in sight - but maybe you'll figure it out quicker than I did!