Combat system

Core stats:

ATK - attack power. Each attack roll varies (roll2d6()*0.15 - 0.8), from -50% to +100% of current value

DEF - defence. Recieved normal damage is ATK-DEF

MAG - bonus attack power for special skills. Also affects max mp and mana regen.

VIT - vitality. Maximum hp = 275 + 30*revari(vit/5). Revari(x) - reverse arithmetic progression sum function.

TAC - tactical awareness / accuracy. Opposite check vs all enemies before each combat is made to calculate chance of ATK reroll.

CAU - caution / reaction. Opposite check vs all enemies, for chance of DEF variation each round. DEF varies each round for x0.65, x1.0 or x1.5

SPD - speed. Opposite check vs all enemies, for chance of bonus action each round.

REC - recovery. Natural healing rate and mana recovery.

Base stats:

Hp - health points. Has a number after 'x' - that is additional quarters of health bars (QBars). If a character loses last hp while still having QBars - he will gain damage gating for 1 round, reducing all incoming damage by x5, and then recover Hp by up to 4 QBars.

Mp - mana. Has a natural regen rate of 2% per round, modified by REC and (2*MAG+VIT)/VIT

St - stamina. Has natural maximum = 60. After combat and extended periods of time, stamina maximum is reduced. Food and long rest restores current and maximum values.

Lv - level. Has absolute maximum of 250.

Monster and players:

Monsters has different stat calculation for leveling up. Monster's max hp = VIT*5+30. Monsters has approximately half DEF and x1.4 ATK compared to player's. But they have twice as less QBars than players.

Normal and critical hits:

When an attack is rolled, and resulting modifier is less than x1.0 - the players put +1 vulnerability on their target. When an attack is rolled and resulting modifier if greater than x1.0, and target has 1+ vulnerabilities - all vunerabilities are consumed and a critical hit is scored.

Critical hit increases ATK by x(1+v) and reduce target's DEF by same multiplier. If a target already has 3 vulnerability, the next hit is always critical.

So if ATK 100 with average multiplier x1.4 hits DEF 100 target - total of 40 damage is dealt. Same values with a vulnerability 3 critical hit would deal (1+3)*1.4*100 - 100/(1+3) = 560 - 25 = 535 damage.

Monsters cannot crit, and instead remove vulnerabilty from themself (reducing value by 1, up to -1).