This is a tactical fighting game, like X-Com, albeit one with a lot of the mechanics (especially the movement / positioning) abstracted out. It is also a visual novel.

The fun bit is combining synergies and combos, which means that a lot of the mechanics don't make sense at first. You start with a limited number of characters and cards, so it takes a while for the game to really take off.

Other games have you leveling up characters and increasing stats based on experience points--Runia doesn't follow this route at all. Instead, there are two progression tracks.

The first track is Invitations. These are a series of pre-generated enemies to face in tactical combat. Defeating these enemies will eventually fulfill each floor's level requirement. When all of the requirements for a floor have been satisfied (usually be defeating multiple different Invitations), this unlocks an Abnormality for that floor.

Abnormalities are, essentially, puzzle fights--easy (or, perhaps, "easy") once you figure out the trick to them, hard if you approach them like a normal invitation. Defeating the unlocked Abnormality increases the level of the library, which opens up another, harder, tier of invitations.

Defeating these harder Invitations unlocks more abnormalities, until you beat the game. Defeating a newly unlocked Abnormality is not necessarily required in order to do more Invitations, but eventually you will need to do so in order to progress.

One thing that confused me was that there are "Characters" in the game with distinct personalities and names (like Roland, the player avatar). However, these are essentially blank slates. Apart from unlockable cosmetics (which have extremely minor bonuses) every character is essentially the same as every other.

What Runia focuses on instead are Key Pages (after the first fight, at least). These pages provide passive abilities (e.g., a 50% chance to increase damage a some attacks), and have more hit points. They are also associated with a deck of cards. You can transfer this Key Page from one character to another any time you like outside of battle, and the passive abilities and associated deck of cards will be transferred as well.

For example, you might have a deck put together to synergize with Bleed damage--all your best Bleed cards combined with passive abilities that work well with them. In one battle, you might want Roland to use them on Floor One, but in a different battle you might want Hod to use them on Floor Three--you can transfer them over without constraint.

As you continue to fight battles ("Invitations") you will acquire more varieties of Key Cards, as well as more battle cards (called "Pages") for your deck. This is the primary form of character improvement in the game.

There is one other form of synergy for characters: Abnormality Pages. When you defeat an Abnormality, that floor gets a series of passive effects that are available at random after any fight on that floor has gone on long enough. These are like Key Pages, in that they give the character synergistic passive abilities, but they aren't guaranteed and can't be swapped from floor to floor.

In this sense, each floor is more like a typical X-Com character, with its own unique stats.

Combat is like most collectible card games, where you have an initial supply of three mana, and a hand of cards drawn from your pre-made deck, with cards that cost from 0 to 3 (or higher, later on) mana to play. The basic rule is that you draw one card and gain one mana every turn, so if you play a three mana card on the first turn, you can only play a one mana card the next turn.

Everyone has a health bar (when it reaches zero, you die) and a Stagger bar. When the Stagger bar reaches zero, they spend a turn unable to take actions (including defensive ones!) but on the next turn their Stagger bar is restored to full and they can act again.

The structure of the fight.

• Everyone rolls initiative.
  
• The enemies choose their attack cards, and indicate which of your people they are attacking.
  
• You assign your people to attack the enemy.

If you are attacking someone who is not attacking you (e.g., they are attacking one of your other Librarians) then it's called a One-Sided Attack. You roll your damage, and they take it--there is no way for them to mitigate the damage outside of whatever passive effects they might have.

If you are attacking someone who *is* attacking you, it's called a Clash, and whoever rolls highest wins (see next section for details). If you assign someone with a higher initiative to attack someone with a lower initiative they will be forced to Clash with you, even if they were previously planning to attack a different person. Essentially, the faster person is jumping in between, to save their slower teammate.

You might choose to do this if there is a card you want to play specifically during a Clash. Or maybe you want to use your higher speed character to save a teammate with lower hit points from getting attacked.

Both players roll dice, and the higher number wins. If everyone involved was using combat dice (i.e., Slash, Pierce or Blunt Dice), the winner does the amount of damage listed on the die to the loser, and that is that. Certain characters have weaknesses and strengths against certain damage types.

It's slightly different for the two types of defensive dice.

For Block dice (the shield) the winner's damage is lowered by whatever the loser rolled (e.g., If I attack you and roll a 5, and you block and roll a 2, you take three damage). If the Blocking player rolls higher than the attacking player (or if both folks are blocking) the the loser takes Stagger damage equal to the difference. So even blocking can be an offensive tactic!

For Evade dice (the curvy arrow) it's more all-or-nothing. If the attacking player wins, the Evading player takes full damage. If the Evading player wins, they take no damage. In addition, their Stagger hp is refilled by the amount that they won the roll, and they can continue to use the same Evade against further attacks.

This is the final basic concept to explain: Emotion. As the fight progresses, the characters individually get more fired up, which increases the amount of mana they have. Characters start with three mana, but when they advance to the next level of Emotion, they get an additional mana *and* their mana bar is fully refreshed. This means that you can play a three-cost card in the first round and, if things go well, start the next round with four mana. Of course, if you don't get the next Emotion tier, you'll be starting the next round with only one mana.

Emotion is gained through certain positive and negative events. For example, Clashing with someone and winning, Clashing with someone and losing, Staggering someone, and so on, each give a "Emotion Coin", and when you have enough of these the tier increases and you get more mana to work with.

In addition, when the average Emotion level for your whole team is high enough, you get a random choice of an Abnormality Page from the pool available to the floor you are on. If the majority of Emotion Coins you've earned were through positive effects (e.g., winning a Clash) then you are offered more of the strictly beneficial Abnormality Pages (these are green-colored). If there were more negative events, then you are offered Abnormality Pages with strong benefits but also some drawbacks (the red ones).

It's the most complicated tactical visual novel I've ever read, but it is worth noting that there is a huge amount of story in this game. It's all skippable, and you can easily fast-forward it if you read faster than the voice actors.

It's all SCP Foundation type stuff, so a lot of dystopian cyberpunk, and some body horror. The section about the stalled Warp Train was especially... well, it stuck with me, you know?