Describe the moment and the device. Is movement uneven during combat? Does the first visit to an area pause? Does a menu take too long to open? Record the build and conditions so measurements can be compared meaningfully.
Measure the actual experience
The developer can profile representative scenes and identify where time or memory is being spent. A guess that the art is too detailed may be wrong; the cause could be logic, asset loading, rendering setup, or another dependency. Changes should follow evidence.
Test a realistic workload. An empty scene on a powerful workstation does not establish performance on the intended phone or lower-spec computer. Likewise, one unusually heavy stress case should not be described as ordinary play without context.
Compare the revised build using the same conditions and check that the improvement did not damage appearance or behavior. Keep the supported device set and remaining limits explicit. Performance is a continuing balance among the game's goals, target hardware, and production budget. A useful review produces a prioritized set of concrete changes and measurements, rather than a promise that one technical trick will make every scene run smoothly everywhere.