Expert rival difficulty¶

Milestone: Unreal Engine 5.8 source-only development. No verified Unreal build, installed Windows executable, Android playtest, or published game.

Player interaction¶

Open Quick Race in the existing in-game Canvas menu. Use BROWSE (N on keyboard, Gamepad D-pad Right, existing Android menu BROWSE) to cycle STANDARD CIRCUIT -> EXPERT CIRCUIT -> SOLO TIME ATTACK -> ROOKIE CIRCUIT -> STANDARD CIRCUIT. The SOLO option uses the existing single-lap Time Attack event and spawns no rival. No new track is invented. See Quick Race mode picker QA. The selection is displayed in the Quick Race menu. Choose Select/Enter to start a NEW race with the selected tier. Closing the menu without starting a new race does not retune an ongoing opponent.

ROOKIE: the real rival's forward motor demand is capped at 0.55.
STANDARD (default): identical to the earlier rival controller; no behavioral change.
EXPERT: raises the planner's already-positive motor demand by at most 0.08 on observed straights with modest speed, never near sharp steering, under braking, at rest, at high speed or after route completion.

All numbers are controller throttle fractions, not guaranteed lap times, top speed or proof of an AI skill rating. Safety decisions for verified gate traces, tire grip, off-track traction, collision damage, engine heat, physical traffic, yaw rate and spin protection still apply. The tuning cannot turn an earlier BRAKE into acceleration.

Career fairness and existing saves¶

This is only a session-local Quick Race selection; no SaveGame fields or ownership/economy changes are introduced. A newly started career event ALWAYS snapshots STANDARD, regardless of the Quick Race selection. Cycling options while a race is in progress changes the pending selection only; the actual rival stays on its last latched difficulty until a successful restart. Invalid/corrupt tier values fail closed inside the motor governor.

Tests and limits¶

Portable C++20 tests cover cycling, names, three distinct throttle outputs, career mode restriction, planner brake/arrival preservation, zero-demand/steering/high-speed exclusions, malformed physics input and 100k bounded predictions. Python source-binding tests verify existing keyboard/controller/touch input parity, the menu, race-latching and ordering before the already-tested AI safety governors.

Real licensed Unreal 5.8 editor compilation, physics behaviour, head-to-head lap-time tuning on different hardware, cooked game/circuit, Windows setup and Android lifecycle tests are still necessary. See release gate #148 and Android #13. This is not a stable release and does not create a playable executable.