In between the alpha and beta builds of the game, the testing department will also have been playing the game to make sure there are no "bugs": nothing that makes the game get stuck or crash, no way to cheat, no loopholes in the rules, etc. They categorise any bugs they find as either "A", "B", "C" or "D" bugs. "A" bugs are the most serious, and include anything which makes the game freeze or stops progression within the game. "B" bugs include problems with the game timing or scoring. "C" bugs are graphical defects, such as a point in the game when a few pixels are out of place or something looks odd or distorted. Finally, "D" bugs include any other problems of a minor nature that are observed by the testers.

These are reported to the game developers as they are found.

After about a day and a half of testing, the game's developers meet with the testers to clear up any bugs. This usually takes around a week. When all noted bugs have been "closed", the testing process starts all over again, "to make sure that in fixing one bug two others are not created". Every single game goes through 5–6 testing and fixing cycles, although each cycle is slightly shorter than the previous one, all being well. Once the beta build of the game is in place and being tested, the graphic artists can continue adding extra refined touches such as placing score cards and putting in much more polished artwork. A game that is nice to look at makes it much more interesting and fun to play.