Mazocarta: A Seeded Procedural Deckbuilder for Instrumented Game Development

TL;DR

Mazocarta is a Rust-based, WebAssembly-compatible procedural deckbuilding framework designed as an instrumented game development tool supporting interactive play, simulation, testing, and local multiplayer, emphasizing reproducibility and balance analysis.

Contribution

It introduces a versatile, deterministic rules engine supporting multiple modes of play and testing, serving as a reference artifact for instrumented game development.

Findings

Simulation pipeline produces reproducible development signals.

Autoplay win rates are consistent across 1,000 seeds.

Framework supports automated testing and local multiplayer in browsers.

Abstract

Mazocarta is a seeded procedural tactical deckbuilder implemented in Rust, compiled to WebAssembly for browser play, and executable natively for simulation. Its primary technical contribution is not the invention of a new deckbuilding genre, but the construction of an instrumented game-development reference artifact: the same rules engine supports interactive play, native command-line simulation, automated end-to-end tests, save/load fixtures, and local-area multiplayer. This paper describes Mazocarta's architecture, deterministic run model, reproducible balance probes, and QR-mediated WebRTC pairing for local multiplayer. An evaluation snapshot over 1,000 deterministic seeds shows that the simulation pipeline can produce reproducible development signals. In the evaluated configuration, single-player and two-player autoplay win rates were 36.1% and 34.9% over 1,000 deterministic seeds, respectively. These rates are not presented as final player-facing balance metrics, but as repeatable probes for future balance shifts and regressions. Mazocarta is positioned as a playable open-source reference artifact for instrumented game development: deterministic regression checks, automated playtesting workflows, balance probes for game mechanics, and browser-native local multiplayer all exercise one shared production rules core.