Work to build the Pontio centre at Bangor University began in 2012 - and it is already a year late opening.
The new centre houses a theatre, digital cinema, students' union, bars and restaurant and business innovation spaces.
A full programme of artistic events is due to get under way from December.
Prof Jerry Hunter, the university's pro vice chancellor, said it was a "great pleasure" to finally make public some of the "fantastic facilities" on offer.
"It has been a difficult journey, but now we have created a transformational centre for innovation in science and the arts in Bangor," he said.
The centre is on the site of the former Theatr Gwynedd which closed in 2008, and was demolished to make way for the new project.
But it has been blighted by delays along the way, and a planned autumn 2014 opening had to be abandoned.
A £50m arts and innovation centre project in Gwynedd is finally getting its finishing touches, university officials have said.