This level isn't really a level so much as it is an exhibition of some scenery techniques and props I've created- mainly a gigantic dragon statue.  The one in the middle holds a key in its mouth if you really must "beat" the level.  A red core makes it look kinda like it bleeds if you attack the chest, neck, and head.
Also experimenting with lava floors and how to create the effect of small pools of lava rather than an unbroken sea, tiling floor pieces, and how to make the lava into a purely aesthetic effect, rather than a hazard.
All in all, I don't think it's too shabby for my very first Voxatron creation.
Lol, I realized after I submitted it that the screenshot is terrible.  I don't suppose there's a way to change it?
And thanks.  It took about a full day or so.  I've been sick with a chest cold, so I've pretty much just been sitting in front of my computer all day. XD
Right now, I'm working on an FFX Bahamut model.
Here's a better thumbnail:
And here's the bahamut WIP, at a whopping 128 x128 x47 voxels:
I figure it's only a matter of time before people start using Voxatron the same way they use Spore and Minecraft:  to create awesome sculptures and/or fan art.
I'm just getting a head start, lol.
And to be fair, I've some experience with modeling dragons in 3D with more conventional software:
GangztaX, you may use these models for your level.  Thank you for asking first!
I don't mind as long as credit is given.  D
I still haven't beaten Dark Forest yet, but I'm actually not that great at this game.  I'm better at building props than I am at staying alive.   And Dark Forest is apparently hard by Voxatron standards, so it may be a while.  Nevertheless, I enjoyed it so I'm looking forward to seeing what you can do with the few props I've contributed here.   ;D
Quick tip for people creating large sculptures with voxels;
Rather than build them voxel by voxel, it is MUCH quicker to start with a solid cube and carve it into the proper shape (this can be quickly accomplished by using the select tool to draw the areas you want to carve away).   Remember that shift subtracts from the selection and ctrl adds to it, so you can define fairly complex three dimensional shapes with a few good strokes of the mouse.  D  This way the bulk of the sculpture can be completed in hardly any time at all, so you can get right to detailing.
I'm going to assume you're talking about the object editor here, but there is, in fact, a symmetry button.  It's down on the bottom left of the screen, next to the options for perspective, outlines, and cage when you're in the object editor.  It looks like a butterfly.
If you're referring to the level editor, then I have no idea.  Since you can create objects as large as the entire clipping plane (128 x 128 x 48), there's no reason not to do it with the object creator.  D
Symmetry can be turned off and on, if you want part of the object to be asymmetrical.  Turning symmetry back on won't mirror any existing voxels, it will only mirror your "brush strokes" if that makes sense.  Like, it mirrors in real time as you edit, rather than mirroring what's already been made.
Easier in some ways.  When you're modeling with meshes instead of voxels, you have to plan ahead a lot more, because tweaking on the fly can be more difficult.  You actually have to be conscious of your geometry, too, which isn't even a factor with voxels.  Also, voxels allow you to create solid objects with actual interiors, something you can't do easily with meshes.  Voxels are simpler, I think, but certainly rougher.  I've also got experience doing pixel art for an online game (dragcave), so as a spriter and modeler, I think I can take what I know from both worlds and apply all those skills here.  D   Like how spriters always make the coolest stuff in minecraft.
I ought to introduce my friends at Dragcave to Voxatron, actually.   I'd say the spriting skills are more important when it comes to palette and silhouette, but the modeling skills really come in handy as good spatial sense is important, too.
And according to Firefox, "voxels" isn't a word.  GET WITH THE PROGRAM, FIREFOX.
What you do with teh solid cube is you make it the color you want the inside of the sculpture to be.  Then you paint the outside whichever colors you want.  D
As far as I know, snap to grid only works for placing objects.  But if you're moving them, just remember that the grid = 4 voxels, so just hit the arrow key 4 times in the direction you want to move it and you're golden.  D