Here's a few "un"achievements: (brackets for some recomended names)
Fail on the last note (at the finish line)
Fail during a spinner (spun out)
Fail with a combo >100 (bleedout/elite deprivation)
(all possible with high hp drain maps and if you have low health before a part with little notes)
Play a map with nofail and get more than half your highscore (which means you would have set a new record if you didn't use the mod) (fail!)
Break >500 combo without a miss (slider/slidertick) (a lost S)
Finish a song without any elite beats (imperfect chain)
(possible for low hp drain maps)
Finish a map without having your cursor leave the slider BALL (not the large ring) (high precision tracking)
Nightcore a song tagged nightcore (uguu?)
Pass a map with all difficulty increasing mods (hardcore)
have a max spin rate twice your average spin rate (unstable rotations)
(striked off those I thought weren't too good in hindsight)
Fail on the last note (at the finish line)
Fail during a spinner (spun out)
Fail with a combo >100 (bleedout/elite deprivation)
(all possible with high hp drain maps and if you have low health before a part with little notes)
Play a map with nofail and get more than half your highscore (which means you would have set a new record if you didn't use the mod) (fail!)
Finish a song without any elite beats (imperfect chain)
(possible for low hp drain maps)
Finish a map without having your cursor leave the slider BALL (not the large ring) (high precision tracking)
Nightcore a song tagged nightcore (uguu?)
have a max spin rate twice your average spin rate (unstable rotations)
(striked off those I thought weren't too good in hindsight)