# Package single level

Due to the differences in behavior between the editor & shipping builds, it can often be desirable to test or debug issues related to low-level game systems like object streaming or serialization in the packaged game. However, often we want to isolate just these issues for testing purposes, rather than doing a full build of all game content. The easiest way to achieve this would be to put together a single test level that contains only the things we want to test, and then package it.&#x20;

While the Project Launcher tool & project settings provide options to ostensibly do just that, in practice, it often results in unintended maps getting cooked, even if they are completely excluded from the list of maps to cook.

The easiest & quickest way to package a single test level and guarantee it opens when the game is launched is to go to Project Settings > Maps & Modes and specify the level in "Game Default Map." This will take preference regardless of whether you have included the map in any "Maps to cook" lists (like the one in project settings, or in the Project Launcher menu). It may still result in other files being cooked that aren't relevant to the specific test level, but as we are only using this for debugging or testing game behavior, that isn't a huge deal.
