Assuming u mean DONNIE DARKO and REQUIEM FOR A DREAM (not bashing the spelling, just making sure), in terms of mind-blowing, i suggest other Darren Aronofsky (RFAD's director) films (they are all mind blowing IMHO) like PI, BLACK SWAN, or THE FOUNTAIN. other suggestions off the top of my head (so I'm probably gonna forget some): CITY OF LOST CHILDREN DELICATESSEN THE HOLY MOUNTAIN NECROMANTIK NAKED LUNCH FEAR AND LOATHING IN LAS VEGAS I SPIT ON YOUR GRAVE JACOB'S LADDER ERASERHEAD BLUE VELVET A CLOCKWORK ORANGE EYES WIDE SHUT PINK FLOYD THE WALL SUICIDE CLUB BATTLE ROYALE THE MATRIX BRAZIL TIME BANDITS just a mall list, and probably forgot some great ones. For some real mind f*cking, try some non narrative films. Look up works by Maya Deren, Stan Brakhage, or Kenneth Anger. Definitely stranger than typical Hollywood fare.
It may sound crazy but give O Brother, Where Art Thou,A Try!There is a lot more then meets the eye with this movie!
not entirely sure what it is you're asking for here mate, since requiem and DD aren't entrely similar, but at a guess i'd reccomend TRAINSPOTTING by danny boyle and KONTROLL by nimrod antall. anything by alexandro jodorowsky is visually trippy as hell, but narratively kind of problematic, my favourite is EL TOPO, although most people i know swear by the HOLY MOUNTAIN, but definitely not for everyone. BRAZIL and FEAR AND LOATHING by terry gilliam. another film i'd really reccomend is PERFORMANCE by cammell and roeg, this film is a real love it or hate it british cult classic, with a very large group of haters and a hardcore fanbase. its insanely trippy but in a washed out, confusing, dark and dangerous seventies sort of way. compared to a lot of "safe" depictions of psychadelic experiences found in a lot of modern films, this one is genuinely unsettling. sort of "get carter/the long good friday" meets fear and loathing. i love it, lots don't. SLACKERS and WAKING LIFE by richard linklater, also A SCANNER DARKLY. if you REALLY wanna blow your mind check out ENTER THE VOID by gaspar Noe, its amazing.
not entirely sure what it is you're asking for here mate, since requiem and DD aren't entrely similar, but at a guess i'd reccomend TRAINSPOTTING by danny boyle and KONTROLL by nimrod antall. anything by alexandro jodorowsky is visually trippy as hell, but narratively kind of problematic, my favourite is EL TOPO, although most people i know swear by the HOLY MOUNTAIN, but definitely not for everyone. BRAZIL and FEAR AND LOATHING by terry gilliam. another film i'd really reccomend is PERFORMANCE by cammell and roeg, this film is a real love it or hate it british cult classic, with a very large group of haters and a hardcore fanbase. its insanely trippy but in a washed out, confusing, dark and dangerous seventies sort of way. compared to a lot of "safe" depictions of psychadelic experiences found in a lot of modern films, this one is genuinely unsettling. sort of "get carter/the long good friday" meets fear and loathing. i love it, lots don't. get some kubrick on as well. SLACKERS and WAKING LIFE by richard linklater, also A SCANNER DARKLY. if you REALLY wanna blow your mind check out ENTER THE VOID by gaspar Noe, its amazing.
While O BROTHER was deeper than meets the eye, and an excellent movie, do you really consider it 'mind-blowing'? ENTER THE VOID is definitely a mind blower... but A SCANNER DARKLY... eh.. Maybe I'm a bit jaded, but as much as I really enjoyed it, I really didn't feel like it was 'mind-blowing'. I'd consider INCEPTION more mind boggling, but I didn't think that was too far out there either (despite being pretty awesome). But one could consider it pretty far out there... so in the interest of fairness lets add a few more that may be considered 'mind blowing' How bout more David Cronenberg? SCANNERS, THE FLY, VIDEODROME to name a few. Hell, you could even add a film like HEATHERS to this list. How messed up was it to see some bullies get a gun pulled on them in the school cafeteria? SPUN and THE SALTON SEA are pretty messed up movies involving meth. SPUN is probably closer to REQUIEM and may be closer to what the OP was looking for (ENTER THE VOID is definitely in this vein of film making). GO would probably be in a similar category as well, tho' I don't consider that one 'mind blowing' either.
Those are hardly cult movies, since you are posting in the cult movies subforum...here are some worthy of that title. Eraserhead A Clockwork Orange Cannibal Holocaust Harold and Maude The Doom Generation Dead Alive