There's a no anvil challenge that delays forges.
There's a 1 pick embark challenge that allows digging while waiting for caravans for the anvil.
>> 0) Embark with food, drinks and animals only.
Food, drinks, 1x of each: milk, fish, meat comes in barrels, so these can be re-cycled for the barrel needs.
Animals, Turkey for their meat, bones, and leather.
So wood will be scarce.
>>1) No metals. That is you can't use metal items. To add more challenges, training axes are also banned.
So limited to wood and bone. Maybe a bone battle axe artifact will be made so it can be used for wood cutting.
>>2) No trading. You also can't loot the caravans.
Does killing caravans considered looting? What if caravans were killed by beasts or goblins, are the scattered items considered looting?
>>3) No mechanism. This also means no draw bridges.
No traps, no bridge, no levers.
Hmm, I can't recall, does upright spear need mechanism? (edit: no mechanism needed, checked the wiki)
>>4) No stones. So you can't build furnaces.
So just wood, clay, sand, and glass furnitures.
>>5) ...?
Weapon: wood training spear, wood/bone crossbow wood/bone bolts. Weapon artifacts made of bone, wood
Armor: leather and bone and wood?
Traps: can't dig? so can't even make a collapsing tunnel.
However, you can walls using wood and glass blocks. Built it high enough and have green glass block garbage dumped from above to kill.
You can make wood minecarts and create some kind of grinder using impulse ramps.
Maybe even minecart shotgun of green glass serrated disc through a wooden block fortification.
Can still use water traps using log walls, wood pump and screw, wood door for water cannons onto high cliff with upright spears (no mechanism is needed-wiki)
Also, can make an entrance safe using ramps and hatches, since hatches are invulnerable when breaching from the bottom.
Using blocks from wood, glass, or clay.
z:1 _Ho where H = hatch, o=wall
z:0 __/o\ where / and \ are ramps.
edit: code format, and wiki check