Rockman no Constancy is a very extensive ROM hack of Mega Man 2, with changes to the music, the graphics, the level design, and the characters. A couple of the powerups from the original game remain, which means that a number of techniques that can be done there can also be done here.

Two versions of this hack exist: "normal" mode and "hard" mode, with the primary difference being no mercy invincibility on hard mode. CUI here plays on "normal" mode and improves on the previous "normal" run by 85 seconds by making extensive use of zipping and death glitches.