Design performance rating

The player builds a design (a coaster track, a bridge, a machine program), the game runs or analyzes it, and a metric vector is computed from what happened. Metrics gate success, set income, or rank the design. In RollerCoaster Tycoon 2, as documented by OpenRCT2, a test run yields excitement, intensity, and nausea from peak positive, negative, and lateral g, number of drops, highest drop, inversions, and nearby scenery; excitement stops rising after 9 drops and 6 inversions, is cut 25% when intensity exceeds 10 with further cuts at 11, 12, 13.2, and 14.5, and is halved when lateral g exceeds 3.1. Poly Bridge drives vehicles over a bridge and shows member stress under a budget. SpaceChem scores solutions on cycles, reactors, and instructions, and Opus Magnum on cost, cycles, and area. State: the design and its last metric vector; update: re-evaluate on test or edit.

Build, test, read the numbers, revise. Players learn the hidden physics through the scores, enjoy beating a threshold, and then chase better tradeoffs between metrics that pull against each other.

• which metrics exist and how many are orthogonal
• formula shape, caps, and penalties, such as excitement penalties for excessive intensity
• hard pass or fail thresholds versus continuous scores
• when evaluation runs: an explicit test run, continuous re-evaluation, or end of level
• how much of each metric's derivation the game exposes
• comparison against other players' results

• Players optimize the formula instead of the fantasy, producing designs that score well but look absurd.
• A single scalar score collapses the design space onto one optimum.
• Opaque formulas require community reverse engineering; RollerCoaster Tycoon 2's rating rules are documented in detail only through the OpenRCT2 project.
• Scores that contradict intuition (a ride that looks thrilling rates low) make the simulation feel arbitrary.

• Designs converge on formula sweet spots, such as stopping at the drop and inversion caps that end excitement gains.
• Multiple competing metrics produce distinct design schools, such as cheap versus fast solutions in Zachtronics games.
• When ratings set prices or demand, design quality couples directly to the economy.

• Can a learned critic rate open-ended designs on qualities like elegance or thrill that hand formulas miss, without becoming a new exploit target?
• Does showing per-term contributions to a score widen or narrow the range of designs players explore?