When movies release a remastered edition, that means they went back, scanned the film again and got a higher-res image.
When music releases a remastered album, that means they went back to the raw files, twiddled their knobs and mixed the audio again. The definition of remaster: "to make a new master audio recording, now usually digital, from (an earlier recording), to produce compact discs or stereo records with improved sound reproduction."
When games release a remastered video game, I expect them to render what they can at higher resolutions, and recreate what they can't. Otherwise, it's a port.
This HD Remaster is basically releasing a DVD copy of a film on Blu-Ray - but before they do, they throw a few filters over the top. Not only is it worse than the original, but it's in no way appropriate to call it a remaster.
The original backgrounds were made using 3D assets. They just need to take a new picture of those.