I've been at work all day so there's been a couple things I've been meaning to post that I just didn't have access to:
I hate to be
this guy but while the jetpack voxel is fucking awesome, it's not accurate to the game at all. If you reference in game cutscenes, concept art, etc, you get a much better look at the jetpack, revealing quite a few things.
1: There is no groin strap. [Multiple sources show this.]
2: The two torso straps come straight down, not toward the belt buckle. [Multiple sources show this.]
3: The little tubes are present. But they're actually just air lines for the scuba gear that clip on the jetpack's webgear. [Clearly shown in the Birth ending cutscene.)
4: There are no exhaust pipes. The bottom of the jetpack is one big exhaust. [Pay close attention to the player sprites and you can see this design persisted past the 1994 concept art right into the released game. Unfortunately the Duke model seems to be under-detailed depending on when it was used, like in the Lunar Apocalypse ending cutscene. Also the actual exhaust hole seems to be untextured, instead relying on lighting, so when it's viewed directly head on it just looks like shiny metal instead of the hole it's meant to be.]
5: The fins actually are present. [Both the fins and the exhaust are hard to see in the original sprites, but very clear in the Total Meltdown sprites, as well as some cutscenes.]
In general, the jetpack mostly stayed the same from the 1994 design.
Media for posterity.
Apologies for my autism.
Also, even though a fire hydrant voxel has already been completed, I would just like to point out that for some reason there was another frame of the hydrant cut from the game, which could have been used to make a "fake" 3D object like many others in the game. Here are both sprites, if you or someone else wanted the voxel could be made "more accurate."