I’ve successfully built on glaciers a couple of times, but that was several versions ago and I have no screenshots. It helps to bring along non-grazing livestock like pigs. And spend any extra embark points on logs to make beds with.

Haunted biomes are the ones that always do me in right away.

I did a savage glacier fort. I wanted to build an ice castle above ground. It had a moat and everything!

I did start with a little bit of taiga on my embark, though, so it wasn’t terribly difficult. Besides the 8 giant enraged sparrows that murdered everything on the surface once or twice.

I had a pretty good fort going in a tundra not long ago. It didn’t fall to chill, or lack of water, or crankiness, or anything like that - I just didn’t account for flying beastmen when making the entrance to my cavern. Batfolk everywhere.

Screenshots and Lemmy is a bit technical for me at the moment, sorry.

I would say that generally in DF, if you can make it to the end of the second year, then you should be in a pretty good place to overcome pretty much anything the game will throw at you. A dry moat with a drawbridge should be pretty doable by the first summer, and that lets you completely shuts down most invader(s) until you’re ready to deal. Doesn’t take all that long to get your metal industry running on magma, at which point iron+ armour and weaponry is easy; get twenty dorfs training for a year with it, and some decent killzones set up which you can remotely funnel enemies into, and it’s almost all good. Some enemies are surprisingly nasty - you don’t want a necromancer to get inside the gates, giant flying undead are absolutely dreadful, and letting a clown out by accident when you weren’t expecting one is liable to be a fortress wipe - but as long as you can get established, then it’s easy enough to deal.

Where’s the worst to get established? Random. I’ve set up in terrifying regions right next door to a necromancer’s tower, and it’s been super tame. I’ve set up in what I’d expect to be a dead easy leafy forest, and had my whole team wiped by crocodiles before they could even pick up the weapons they brought with them. Worst start I ever had was in a pre-Steam version, where the evil blood rain melted the skin of anyone caught in it, which I think lasted about three frames after the initial unpause. (Worst evil rain I’ve ever had in the Steam version was one which caused all of my cats to rot when they were caught in it - the miasma they dragged around the fortress before they final dropped dead nearly caused the whole fortress to collapse out of anger - but mostly it seems to just cause years of PTSD for anyone caught outside in it.)