When I wrote the session recap / review of LotFP: Weird Fantasy Roleplaying, I mentioned that I hadn't read Weird New World yet. I did read it later that week, but never got around to writing up what I thought of it. So here is my review. There will be SPOILERS, of course, so skip this if you don't want to see that sort of thing.
I have the sense that Mr. Raggi & I were reading the same books recently. Last year I read Dan Simmon's Terror, and Anthony Brandt's The Man Who Ate His Boots. Weird New World is heavily influenced by the search for the Northwest Passage, and I saw a nod in there to the monster from Dan Simmons' book. If you're planning on running this, I think you really do need to read one of the above books (or another about the search for the Northwest Passage), if you're going to get the flavor right.
The module is a sandbox, which is great, but it's mostly very very sparse on detail. You'll have to put a lot of work into this to play with it. It's more a campaign sub-setting than any kind of adventure. Most of the encounters listed are bare-bones, a few lines of great ideas, but all the work is left to the DM.
In practice, I can't see players just wandering about this wilderness aimlessly. The environment is deadly in the extreme, and they're going to need a reason to head out there, and probably some halfway-decent idea of where to go in particular, if you want to do more than watch the party flail around for a bit and die of exposure. So just stumbling across the encounter areas is unlikely. This is good and bad - good because you don't have to detail everything before the players set out, bad because they won't run into all the wonderful awfulness that's out there.
I really liked the map, it was really well done and very reminiscent of the arctic reaches of northern Canada. The only fault I find with it is the numbered encounter areas. The numbers are very tiny, and hard to pick out. Putting text labels next to the encounter hexes, in addition to the numbers, would make it easier to use.
Mr. Raggi did describe two encounter areas in greater detail, the pirate lair, and a ship impaled on a coral spike. The pirate lair suffers from the same issues that the the Tower of the Stargazer had - players are punished very very very badly for curiosity. If you go through all the work of getting past the lava and/or rivers, you most likely just end up being screwed over for your ingenuity.
The coral spike didn't have that sort of punishment. It is a bit lighter of an encounter though. My only quibble here, which probably won't bug most people, is that it is patently impossible from a nautical perspective. The sailors in my group would never suspend disbelief - boats that don't leak when pitchpoled onto giant spikes. Probably not an issue if you're not dealing with sailors, but I could never get away with it.
All this said, I probably won't be using this anytime soon. I'm in a Thundarr-inspired megadungeon right now, and wandering off into the Great White North isn't in the cards right now. When they get down to the lower levels, with the teleporters, black ziggurats, and other low-level tomfoolery, I expect I'll drop in a gate to the frozen north.
I've also been turning over in my head my criticisms of both this and Tower of the Stargazer, in respect to the player-punishment. I've read similar critiques of Death Frost Doom, which I also purchased, but have not yet read. I have to compare what I've read, though, against my actual experience running the Tower. The players mostly avoided the death traps, by being too scared to mess with anything, with the exception of the telescope. I'm curious to know what lethality other people have experienced when running through these adventures. I've only read speculation so far, and one run-through of Death Frost Doom where the party didn't touch anything at all.
I also forgot to mention in the Tower of the Stargazer post, that the "game for your soul" section was very well received. I only had 2 players, and both got involved with the game of checkers (chosen because it would be shorter than chess). It was a big hit.