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I'm working on a new game that reuses a lot of Souvenir's code, so lately I've been doing more research into non-monoplanar first person movement, meaning you're not limited to primarily moving along the X and Z axis / traversing across a single, fixed, designated "ground" plane.
Traditionally, "noclip" flying / spectator modes have been the most common form of non-planar first person movement. However, I'm not a fan of it as a movement mechanic because you're always "right side up" above a ground plane. Your idea of space never really changes because that's not the point.
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Shattered Horizon (2009) was a multiplayer FPS in space, where astronauts shoot each other while hovering around asteroids. From what I can grok in gameplay videos, players can rotate and hover freely, but they almost always maintain the same common "ground plane" as if there's a "right side up" in space. Common map layout terminology and directional lighting also reinforce the idea of a "top" of the map.
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Flip'd is a 7DFPS about flipping gravity / walking on ceilings, and it joins a similar FPS project Delta-G. I don't think these work because they discard a very important rule from VVVVVV: that you must land on the ground before you can switch gravity again.
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Thus, these games are less VVVVVV and more like Flywrench, where "hard puzzles" involve hovering around at high speeds while juggling other problems. Seeing as a two-dimensional Flywrench is already really hard by itself, I don't think it needs another dimension of death as well as a constantly spinning camera.
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Prey (2006) was an idTech4 FPS with a Native American protagonist (yay!) who walked on walls and ceilings but only on special tracks or by passing through certain forcefields (boo!). I think this design was the most immediately compelling, but the implementation was lacking. It was too much of a scripted level design contrivance that didn't allow for any emergent player strategies -- so basically Prey came up with a cool movement mechanic (as well as portals!) but then didn't really do anything with it.
Uhh... oh, hm. That's a pretty short history, I guess.
The lessons I'm taking away:
- Don't give players direct control over their roll, because they'll always just choose the easiest orientation and stick to that. (Shattered Horizon)
- Don't allow mid-air orientation changing, or else skill-based hovering becomes the most difficult challenge / dominant strategy. (Flip'd, Delta G)
- Don't confine this awesome mechanic to a small portion of a small subset of your levels. (Prey)
EDIT: debate about "Descent" is below in the comments... but to summarize, I think it's important in these games that you're a "person" / biped / creature who walks, crouches, sprints, etc. are flight simulators also first person games if you move around based on a concept of acceleration / thrust / pitch? I don't think so, but let's argue it out!