Well made, scary, and 80's campy
Even back in 1989 when this showed up on HBO, my room-mate and I christened it Most Excellent.
Includes an engaging plot and some scary moments. If the actors had reigned in their "acting" this may have been a serious horror-thriller. But Sheen and company play some of their parts way over the top- which lends to some unintended comedic scenes (e.g. coffee pot scene).
A unique, if dated, film that I have revisited many times. It's fun entertainment.