Game Overview

Cyber Arena is a compact autobattler shaped by the same design pressure as Dota Underlords Knockout: short sessions, fast pivots, and a lot of value packed into each round.

Core Loop

Pick one of three starter boards.
Spend gold on heroes, rerolls, and item choices.
Place units, assign items, and commit to the fight.
Resolve combat.
Collect rewards and repeat.

Reference Math We Keep Visible

Rule	Practical effect
3 starter options, 1 free reroll	Early decisions matter, but the opening is not purely random.
4 lives total	Every loss is significant.
Start at level 5 with 1 XP	The first upgrade happens almost immediately.
`+1 XP` per round, `2 XP` per level	Levels advance on a fixed cadence.
2 copies for 2★, then 2 more for 3★	Three-star heroes are reachable inside one short match.
Base gold starts at 6 and climbs `6, 7, 9, 10, 12...`	The economy supports active rolling instead of hoarding.
No interest, no streak gold	The game is about tempo, not banking.
Items appear on odd rounds	Each loot decision has high impact.

Why This Matters

This structure keeps the match readable on small screens and makes the UI expose the right information at the right time:

current lives
round-based gold
level and XP timing
starter rerolls
item reroll availability
2★ / 3★ breakpoints

The frontend is responsible for interaction and visual feedback, while the server handles battle simulation and state persistence.