Bitmap Vs Vectors

[SPH]

I have a few questions about an upcoming game. Let me explain:

Let's take the game "Worms" as an example. The scenery (and therefore the ground) is either in BMP (or other image format) or in vector format. I think it's in bitmap format, not vector (although I'm not sure).
The ground is easily calculated so that the worm can move around.
The terrain is a large block, not necessarily flat. It has elevation changes.

But here's the problem: when a weapon explodes in the game, the scenery is damaged. This creates holes in the ground for the worms. The ground calculation for the worms is easily recalculated. But if the scenery is in vector format, it's much harder to damage it after an explosion. On the other hand, vectors are easily zoomable. Bitmaps are not.
Another thing: if I use a bitmap for the scenery (the ground), it will be a large block that I "DisplayTransparentSprite" in each rendering loop (I haven't tested the speed, but it might be problematic...).

I would like your opinion on the technique to use and also see if you have any tips...

[idle]

3D engine would be the best option like if you want outline shaders on the terrain

Sprites and if you need zoom draw vectors to array of sprites, for the terrain use a mask image, blow holes in it, combine and redraw sprite and use the mask to work out worm height on terrain.

If say you were thinking along those lines from seeing the AVGSceneGraph (which isn't ready for that yet) you would just modify a pathBezier spline on the fly by deforming or inserting points along an arc where the explosion intersects the path which your worms would then automatically follow.