The game's engine was designed from scratch for "Sudeki" based on the Xbox hardware. To ensure minimal load times, the developers directly streamed data through the Xbox's hard drive, cutting down on memory usage. The team wanted to push the Xbox to its known limits, but also used techniques such as rendering static geometry with pre-established push buffers to take workload off the console's CPU and GPU. The lighting system had dedicated lighting and shadow effects for different body and character types, and dedicated software protocols were created for animating faces and expressing emotions; player characters had fifteen facial shapes, while NPCs had eight. Finding and addressing bugs was a key job for both Climax and Microsoft, who play tested the game in tandem in Britain and America. Notable bugs that were found included graphical glitches with character models, and Ailish's tutorial sequence where her healing spell killed her.