If you're looking for a challenging and thought-provoking experience, Manhunt 2 is definitely worth checking out.
While there was never an official "Uncensored" retail release for the PSP (all US retail copies were rated 'M' with blur filters), the "uncensored" ISOs found online are typically fan-patched versions of the (USA) or ULES00756 (European) releases. These patches remove the seizure-inducing filters and restore graphic details like decapitations and blood pools. Review: Manhunt 2 (PSP Uncensored) manhunt 2 usa uncensored iso for psp