By reaching an ENJOY LEVEL of 120 in Dance Dance Revolution X2, a new Challenge Chart is unlocked for the Dance Dance Revolution Extreme Song "bag". While it appears identical to the Expert Chart, every triplet (12th, 24th, 48th note) step is rounded to the nearest 64th note, making it harder to time. This references how, in its debut game of Extreme, triplet notes were improperly quantized due to hardware limitations, further exacerbated by "bag"'s BPM of only 65. The Expert Chart's timing was previously corrected in Dance Dance Revolution X.

The song "deltaMax" was originally written by DM Ashura for DDR Forever, a StepMania-based fan game for the Dance Dance Revolution series.

The song's inclusion in Universe 3 marks the first time a BEMANI original song originated from one of these BEMANI simulators.

Challenge Charts were included when the song was added to Dance Dance Revolution X2. These charts were created by DM Ashura himself and originally intended to be used in the Expert difficulty.