Zombie 4: After Death(1988)
On a isolated island a group of scientist try to find a cure for cancer but they accidentally the raise the dead when they anger a voodoo priest. The priest raises the dead and kills all the scientist but one couples daughter survives and escapes while they were eaten alive by the undead. The daughter returns to the island many years later with a group of mercenaries and researchers however the walking dead still are on the island.
The also titled After Death, Zombi 4, and Zombie Flesh Eaters 3 in the United Kingdom.
This is the "After Death" trailer in a different aspect ratio and without watermarks.
After Death (alternate title) Trailer