93.2% of individual checks pass, 55.3% of tasks actually succeed.

GameASG-Bench builds 47 browser game-generation tasks across 12 genres, each with an evaluation interface declared before generation. Across nine agent stacks the highest mean runtime check pass rate is 93.2%, but the highest strict task success, requiring every applicable check, is 55.3%. Averaged check rates hide task-level compliance, and the two tested harnesses each got 18 strict successes while overlapping on only ten tasks. Same harness, same model class, different tasks solved. Reasoning effort didn't behave monotonically.