Instructions
Begin or resume a singleplayer game in "StarCraft 2."
Gain unlimited credits through cheats by hitting enter during a level and typing "WhySoSerious" in to the chat. Hit "Enter." You will gain five million credits each time the code is entered. However, achievements are disabled when cheats are activated.
Gain unlimited credits through the research system in the game. During the singleplayer, the player finds Zerg and Protoss research points during missions. After collecting 25 for each faction, the player is awarded 10,000 credits for each additional research point found. The game allows you to replay previous missions, so just replay a mission where you obtained research points, such as the first mission, and you can gain an unlimited amount of credits. This option does not disable achievements.