Sprites facing different directions (angle-wise) would be cool, or 3D sprites in the style of the Nintendo 64

Will it be possible to have sprites stacked like this, though?

If you notice in 3D games, in most cases, the trees aren't really fully 3D models, the leaves are stacked 2D sprites set at different angles, to make the tree leaves look like 3D.

@DJ: Yes. In fact, that (and multidirectional sprites) are already possible; the client just needs to update the sprites being drawn based on the camera direction.
@willrandship: No, not immobile. What I mean is that the images being drawn views of a 3D object from different angles. When you "turn" the sprite, you look up what image will be drawn based on the angle.

As many as you want, limited by only memory and speed considerations.

I've always wondered if there was a way you could have a sub class of sprites in a ray caster that didn't stay perpendicular to the camera, who's orientation would be set, and therefore would be stretched according to perspective like a wall. This would come in handy because it would be flat and have transparency, allowing for objects like a chain link fence or iron bars blocking a path. Would this be easy to do? I only know the very basics of ray casting, and only in the context of a fixed angle ray caster.

:O

TRANSPARENCY?? Wow that made my day...well... night (it's 2 AM )

Transparent anything, or just walls? Having transparency is nice at any rate.

Transparent as in "holes in walls", not glass (glass would require drawing all the walls from farthest to closest).
EDIT: Blarg. The fact that my blocks each have four faces makes the fences look rather strange. It also makes the engine very slow, so never mind it