Ever since the new Riddick movie was announced, it has been intended to be a hard R scifi movie. Much smaller and closer in tone to Pitch Black. Throughout the production the R rating was just assumed, and hoped for, but there was no real confirmation if they’d get it.
Thankfully Universal held up to their word of allowing Towhy to make a R rated scifi movie, as it’s now confirmed that Riddick will released with a R rating. Perhaps the success of Prometheus soothed Universal’s fears?