The costs here are very approximate. The ideas I wanted to get feedback on are:

Turning the fortified land into a creature makes sense because then it's more vulnerable. Does it similarly makes sense to try fortifications that turn lands into other permanent types that can be destroyed?

This has a mana fortify cost, but that's very rarely going to matter more than once. "Equip sacrifice a creature" made sense, but may possibly be too harsh to use on all fortifications. Can normal mana costs work, or do they just not feel fortification-y? How about sacrifice a land (or "when they becomes unequipped, sacrifice fortified land"), can that ever be made to feel flavour? Is there any other "sacrifice an X" that could work?

I think normal mana costs should be the default fortify cost. Perhaps most of the animate-y fortifications could have other fortify costs, but I fear those shouldn't be common. I think most fortify costs should be mana.

Turning fortified land into an artifact doesn't actually help as much as you think. If someone has a Shatter, they'd normally rather point it at the Fortification itself, rather than the fortified land.

Good point, being an artifact doesn't usually help.

I agree animating isn't very common, but the "0/4 wall" was the best common fortification I thought I'd seen so far, assuming "would be just as good as a normal artifact" is a deal-breaker. (I'm not sure, maybe other people are willing to live with most fortifications being equally good as non-fortifications?) which was why I was going with it for the moment.

I agree, by default, normal mana costs make sense, but only if being able to re-equip easily isn't a problem, which it is with "becomes a creature" (or any other fortification which makes the fortify relevant by making becoming attached being a risk), which is why I was thinking of it.

I don't think the idea of animating is automatically uncommon: there's Glint Hawk Idol, Lifespark Spellbomb, and a few others. It was just the nonmana fortify costs I thought shouldn't usually be common. I do see the point about discouraging shifting the Fortification around too easily when it's making the fortified land really good, but we do have to balance that against the complexity of nonmana fortify costs.

Oh, I see. OK, then I agree animating is ok. I don't think sacrificing is a great idea at common, but I think we could do it if it's the only answer to making sufficiently strong fortifications without them being effectively unkillable. (In fact, this is mostly a problem with animating fortifications, where endless recurring a creature is very strong. If we can come up with sufficiently many non-animating fortifications, I agree we may not need it, I just wasn't sure if we could.)

Another possibility would be to look for other "free once but hard to repeat" costs, like "exile ten cards from your library" or "exile N cards from your graveyard" or (possibly) "pay ? life". That would in some way be better for animated or other strong fortifications (excluding the black connection) than sacrifice, but neither of those is very flavour appropriate and both were just done in innistrad -- does anyone have any other similar suggestions?

This card looks like par for the course of what we want to seeing. Good first tack, and a good model to coral the rest of the cards around. The name is almost funny how it gives the wrong impression, though. This is more like a continuous barrage of grapeshot catapults, and less like a gigantic cannon that smashes in walls.

But Mined approaches is the Grapeshot Catapult... :P

FWIW, the reasoning behind "seige cannon" is that it shoots over all the normal combat to very slowly batter the ultimate defending place into submission, rather than being used tactically. And sounds more impressive than "grapeshot catapult", I'm surprised you can catapult grapeshot hard enough to do any damage at all, actually :)

You might not be able to. I tried Wiki-ing the info, but got very little off the search "Grapeshot Catapult". So I googled it, and kept getting back the Magic card Grapeshot Catapult. I know that grapeshot cannons were some of the most deadly weapons in the Napoleonic and American Civil War, ripping through whole battalions... but it might have required the force of a cannon to make it a practical weapon. Otherwise, a catapult would probably need to bundle up the grapeshot, and expect it to explode on impact... but by that point, you lost a lot of the momentum of the package upon impact. Alternatively, it could explode mid-air... but really, who's going to time that thing?

That sounds about right. A look at wikipedia, and what I remember from reading Bernard Cornwell :) suggests the relevant types of projectile are:

• round shot = cannon balls, travel a long way but (obviously) only hit one thing at once
• grapeshot = lots of little balls fired out of a cannon, completely devestating to infantry, but short range. (cannister shot is similar)
• shrapnel shell = like grapeshot, but the container explodes some distance ahead of the cannon. However, it seems that the explosion solely ruptures the container, so serves to turn a solid projectile into a crowd of little ones, but doesn't scatter the bits with lethal velocity itself: basically it it gives grapeshot longer range. But the lethal force still comes from the cannon.

All that existed in Napoleonic wars.

• explosive shell = invented during WW1, but shrapnel was still widely used. Confusingly, it seems "shrapnel" is still used to refer to the little pieces, but "shrapnel shell" specifically refers to one that doesn't really explode by itself.

The explosive shell is the only one that's really dangerous at low velocity.

So if you were aiming at flying creatures, I'm not sure, but it seems you'd never hit them with roundshot, if they're close enough grapeshot would be just as devestating as on infantry, shrapnel (which could plausibly be called grape in fantasy) would work similarly but less well at a distance, and an explosive shell would be ideal (just get it anywhere near and hope for the best, I think you could calculate the height you wanted it to explode closely enough), but be high technology for a fantasy world.

It's not clear to me what "grapeshot catapult" is. I don't know whether or not you could give graveshot sufficiently lethal velocity with a catapult -- I guess you give more than enough energy , if your catapult is built to hurl giant rocks, but I don't know if it could be fast enough.

But Grapeshot Catapult to me suggests this isn't a devestating explosion (else it would be three damage once, rather than one damage every time), but rather, hurling a lot of grapeshot with a catapult at too long a range and hoping for the best -- that it might do some damage if you get a lucky ball, but not more than that. (I imagine the name was chosen for flavour rather than military accuracy :))

A rather strange entry to the file in that this card doesn't take advantage of its 'fortify-ness'. I'm cool with that, though. It's got good flavor, and shows players what the fortifications could have been if we weren't stretching so hard. Added to file.