floors and falling

Well, I've successfully coded some routines so that every time a unit moves forward, a check is made to see if the ground it's standing on is strong enough to support it. If they step onto a weak tile, (for example, say something has been damaged by an explosion, or the unit is a 4-ton tank and it's driving inside of a house) it will break through the floor and fall down. It will keep falling until it hits something that can support it, (or until it reaches the bottom z-level) No damage is currently done, but it does keep track of the distance that the unit fell. I'll likely institute falling damage, based on some preset 'free' bit of cushion based on whatever a unit's species/training may be, how much weight they're carrying, how far they've fallen, and perhaps how many spare TUs they have when they've hit the ground.

Next I'll need to write some sort of recursive function, perhaps, to check if every floor tile is being supported by something strong enough. I'd like to incorporate the aspects of X-Com Apocalypse that I found nice; and one of those was a destructible city. I want a high-explosive round to be able to topple a 3 story house. (though, the residents wouldn't like it that much and would likely demand compensation)

I'd like to make this game a bit more dynamic than X-Com was. Things I plan to include:

being able to jump various distances.
being able to climb over various things.