An update: When the game is built and launched externally from the editor via the Launch option, the translucent material with opacity set to 1.0 is still rendered as partially see-through, like it is in the editor.
Though when the opacity is turned to 0.0 and a refraction constant of 1.52 is plugged in, the material does appears refractive, but there is still some issues with the front-facing faces sorting, as seen in the half-torus on the left in the second screenshot attached to this comment.
