People tend to use the terms "remake" and "remaster" pretty interchangeably, but in truth they're two different things. Capcom's Resident Evil recreations — first of the original RE, now of Resident Evil Zero — demonstrate that point quite neatly. While people cutely refer to them as "REmakes," these are remasters through and through.
Resident Evil Zero HD does not offer some comprehensive top-to-bottom overhaul of the franchise's largely overlooked GameCube prequel. Graphically, it looks fantastic, to be sure... but all the quirks and characteristics of the 2002 original show up in full force here, preserved carefully in high definition. The only nod to modern sensibilities it includes, mechanically speaking, is the ability to control your protagonists with a slightly friendlier setup; the old-school "tank" interface remains present, if for some reason you swing that way, but you can also use a more intuitive relative control scheme.
Switching away from the original tank interface doesn't radically change the game, however, and Zero is undeniably cut from a pre-Resident Evil 4 cloth. It still uses pre-rendered backgrounds, which remain static with fixed camera angles, and enemies and heroes alike trudge forward with an almost comical sluggishness. Whichever control scheme you go with, Rebecca Chambers still rotates in place to draw a bead on advancing zombies, with targeting options consisting of "high," "low," and "middle." As in the olden days, all sorts of unhappy shenanigans tend to happen around the transition points of backgrounds — if you step over the invisible line that flicks you from one camera perspective to the next, any zombies that happen to be following you will materialize from thin air right in front of you as they advance.
It all feels a little archaic after a decade-plus of RE4-inspired modernization, though that isn't necessarily a bad thing. It's a different approach to survival horror, one that feels tenser and less like an explosive action movie than the over-the-shoulder camera style of the modern series, and it's perfectly valid. But it does sit at odds with the remastered visuals, which look miles beyond those of the GameCube original despite being drawn from the same source material.
Resident Evil Zero HD, perhaps inadvertently, stands as a testament to the fact that game mechanics and game tech tend to go hand-in-hand. We had 2D platformers and turn-based RPGs in the '80s because hardware lacked the power to create effective 3D worlds or real-time role-playing combat. Likewise, the fixed angles and slow pace of the classic Resident Evils were a matter of necessity on PlayStation, because the hardware couldn't output real-time 3D while still offering the level of detail and atmosphere that became the series' trademark. Heck, the original Resident Evil predates PlayStation's analog controller, so accurate 3D aiming was practically impossible anyway... especially at the system's low resolution.
The HD remaster brings the backgrounds and character models up to modern standards; handily, the original development team produced assets at much higher resolution than the GameCube actually supported, so this new version didn't require everything to be reconstructed from the ground up. Aside from some minor cosmetic tweaks (e.g., every sign in the train at the game's beginning said "DINING CAR," which didn't read clearly on GameCube but resolves in HD and makes no sense... except, of course, in the dining car), the backdrops and character models in this version are simply cleaner, more detailed versions of those in the original game.
There's a bit of cognitive dissonance that results from the clash between modern visual standards and vintage RE production values. The remaster carries over the original voice acting and motion capture as well, which means RE0 combines the awkwardness of classic Resident Evil with the fidelity of modern consoles. The merger can be strange — but on the other hand, the result really does feel like the video game equivalent of remastering a vintage film for Blu-ray. The stiff animations and awkward aiming features are simply artifacts of a different era, like being able to spot matte lines and film grain in an old movie reissued in high definition. Authenticity can be charming, and RE0 feels more like an act of preservation than of reinvention: The best possible way to experience a classic game without radically changing the experience itself.