Mirror (MR) mod icon
For the full list of all mods, see: Game Modifier
The Mirror mod is a game modifier for osu!mania that attempts to aid left-hand-dominant players in playing beatmaps that were originally mapped with right-handed patterns in-mind. The mod achieves this by reflecting the notes across a virtual y-axis that runs down the middle of the osu!mania keyboard. I.e., it "mirrors" the notes. Specifically, the mirroring of notes is as follows:
Comparison between a regular play (left) vs. a play with the Mirror mod enabled (right) in osu!mania
The reasoning behind this is that many osu!mania beatmaps are mapped by right-hand-dominant creators, and thus many of the beatmaps patterns are made to be more comfortable to right-hand-dominant osu!mania players. Thus, many left-hand-dominant players — particularly higher-ranking ones — feel that the mirrored note placement caused by the mod allows their left-hand to be utilised more effectively.