Race Engineer v1.2 is an engineering-first motorsport game about running one car from the workshop and pit wall. Study telemetry, plan named tire sets, fuel, pit windows, and weather contingencies, then make every call yourself. Five rival teams use component builds, tire wear, heat, fuel, and deterministic 120 Hz physics, with no hidden grip bonuses. Review decisions after each race and reuse evidence through an engineering notebook. Built largely with GPT-6 Astra in Codex. Free for Windows.