Brainstorm (1983)

Research scientists Walken and Fletcher develop a device that can record and play back physical, emotional and intellectual sensations from the brain, allowing anyone to re-experience them in exact detail through a tape and headset.

Successful demonstrations get their project some corporate funding but also attract military 'observation' of the device's development. 

Pacifist Fletcher argues against the military intrusion, straining a suspect heart already overloaded by her conspicuous chain smoking, and then succumbs to natural causes while still hooked to the recording machine.

Walken becomes obsessed by the possibility of experiencing Fletcher's last tape. Forbidden to risk it by benevolent boss Cliff Robertson, and eventually banned from his own lab on military orders, Walken gets comprehensively miffed by the discovery that the heavies are nefariously refining his device into a brainwashing tool.

His rampage of revenge, with Natalie Wood and other old comrades in tow, is achieved by cracking computer codes and causing remote-control chaos in the labs. And his hard-won glimpse of heaven is eventually filched from Fletcher's tape via the public telephone network.

Sadly, the device and its tedious effects provide the meat of the movie. 

The protracted multi-million dollar production also suffered the traumas occasioned by the untimely death of co-star Natalie Wood, and a limbo period when the studio (MGM) threatened the withdrawal of completion funding.