A little proof of concept thingie inspired by game mechanic #083 of the 300 game mechanics.
Move around the map using your wasd keys.
The technique is simple: a bunch of PRE tags are positioned on top of each other with slightly different font sizes. The bottom tag is 10px, the next one 10.5px etc. For added clarity I've also made the upper tags a bit darker and somewhat transparent.
Zooming is easy to add, just show a smaller portion of the map and increase the font size.
You might notice that I didn't add the blue slashes background from the mockup, but that's easy enough if you really want it - just put each tile in its own tag. With more clutter, as in a real game, it's probably more helpful than in this little thing.
All in all it's a pretty nifty effect, 3D-ish but still very ASCII. Later(tm), when I make my own roguelike I'll see if I can't do something similar. Just need to figure out a workable way to combine this with SVG.