Vivid Knight is a roguelike dungeon crawler and strategy game.
You start with one of two Heroes. Your Hero determines your starting resources as well as your party size. Your resources and progress get reset and you start out at zero again after each dungeon. Your reward for winning a dungeon is 30+ crystals. With crystals, you can unlock new minions, spells, or accessories for future dungeons. If you lose in a dungeon, you will get nothing.

Battles
Vivid Knight is an auto-battler to some extent. You can’t decide what your minions do; they will attack automatically. After each turn, you can play one of your spells. That’s basically all there is to battles. It may sound pretty underwhelming but it isn’t. In fact, there’s substantial strategy involved thanks to all the different components of the game. It’s important to think about which minions you use and which spells to play when.
Minions
You get to choose one of three minions at the start of each dungeon. On your way through the dungeon, you can find minions in chests, get them as a reward, or even buy them. There are different tiers of minions (bronze, silver, and gold). If you obtain a minion three times, you can fuse them into a stronger version. It’s still bronze or whatever tier it was before, but gets a little star on the picture and its stats get better.
Talking about stats, they’re the same as in most other games (HP, Attack, Defence, Magic, and Speed). Speed decides the order of attack. Each minion also has special abilities and two symbols that can get you bonuses if your accessories have the same one (e.g. 1% damage on all attacks, +x fire/shock/ice to all enemies at the start of a battle, etc.)
Dungeons
Each dungeon has several floors. The first few dungeons have just 2-5 floors and you’ll likely beat them each in like 10 minutes. The fifth dungeon has 10 floors and can take up to an hour, and so on. To reach the next floor, you’ll need to find a key to unlock the door.
Each floor also has several events, such as a jeweler, alchemist, and special events. (For example, you see a statue and take one accessory from it.) At the jeweler, you can buy and sell minions, whereas the alchemists will let you craft spells for materials.
Crafting spells are random. You see like 20 spells and can pay 20 materials for one random spell. Each dungeon has at least one boss fight and each floor gives you special rewards.

Currencies
Aside from materials, which you’ll get plenty of during your run, there is also gold and mana. With gold, you pay the jeweler or use it to increase your party size. With your starting hero, you can have up to 6 minions in your party.
Mana is there to move around. For each field you move to, you need to spend one mana. After each floor, your mana gets refilled but you can also recover some with spells. If you move around without mana, your minions will lose HP.
Overall progression
You can unlock a second hero after beating a certain dungeon and has different stats, as mentioned above. Aside from that, you need 10 crystals to let fate decide what you will unlock next at least, to some extent. You get to see three things and can choose one of them. It gets unlocked and you can find it in a later run. Sometimes, when you try to unlock something new, you can permanently increase your starting mana or gold (+1/+10). As of now, there are 78 items you can unlock.
After around 2 hours, I unlocked 18 of them. Keep in mind that I did not lose a dungeon at that time. Vivid Knight should offer quite a few hours of fun.
I did not encounter any bugs and the English translation is pretty good. The music can be annoying after some time, but maybe that’s just me.
Difficulty
Thanks to RNG, there is always the possibility to have a bad roll. Also, enemies will get stronger on each floor. Overall, it’s not an easy game. The first few floors (dungeons) will feel pretty easy and can lead to complacency, but starting from the fourth dungeon the game starts getting significantly difficult. You really need to upgrade your minions to stand a chance and also increase your party size whenever you can.
Repetitive?
In a word, yes. While the game is fun, it does feel repetitive. You do the same thing over and over again and start from scratch each dungeon, but this isn’t a bad thing necessarily. As the game got harder and dungeons longer, I wasn’t thinking about it anymore. I just wanted to beat the next floor and the one after that. The addictiveness of similar games kicked in and my mind told me to just “play one more run”. The only thing I would like to see added is a fast mode to speed things up.
Summary
Vivid Knight offers a strategic experience that catches your attention pretty easily if you’re into roguelike dungeon crawlers. It isn’t as engaging when you’re just starting, but it will quickly become addictive thanks to harder dungeons a bit later on. There’s enough content for several hours of fun and the price is fair.

If you’re into strategy games and the art style doesn’t turn you off, consider getting Vivid Knight.
This is one of the best reviews in the history of mankind.