Spoilers ---
There are four endings (three real ones, one is more of a "game over" kind of thing). Two were in the original game - you got one of those, the sort of "good" ending for that version. Then two others were added for this remake, another "bad" and "good" ending. The steps to get the last one are admittedly kind of convoluted.
I think the endings and the steps to reach them are laid out in this video: https://youtu.be/mvwznC04LRk