First up is the trailer, there's not as much to be said about this as the gameplay videos, so screenshots aren't quite necessary. In this we see our hero, Connor, assaulting British troops who were preparing for battle, laying waste to those in his path and eventually taking down their Templar leader. From Ubisoft's press conference last night we have learned that the British officers are not the only Templars in the game, with enemies being colonists as well. Also note the addition of the bow as a likely usable weapon in the game.
Next we have the real show-stopper, the gameplay demo we saw at the Ubisoft press conference. This shows Connor starting in the snowy wilderness of New England.

First we witness the new freerunning system as our hero leaps and bounds from tree to tree with grace befitting an Assassin's Creed main character.

Next up is a hunting scene, where Connor slays a deer for it's meat, and then..

...is attacked by wolves!

Moving swiftly on, it turns out the meat-gathering was for a quest!

This shot gives us a good look at Connor, and am I the only one who thinks he's awfully native looking? It's also refreshing to have someone who doesn't look exactly like Desmond, for once.

Here's a controller and ingame shot of a pre-combat scenario, shortly after Connor skillfully hangs the man to his right from a tree. Following this was some combat, but I failed to capture any of it. We got to see some new counter-kills, as well as a few repeats.

Sliding down the hillside! This is the kind of thing we've never really seen in Assassin's Creed. This gives a hint at the sheer size of the playable areas, ranging from wilderness to cityscapes in all kinds of weather, stretched across 30 years!

Connor infiltrates the British camp to find and kill his target Templar.

And in the mean time, he sees fit to blow some stuff up!

Going in for the kill in a classic Assassin's Creed style, we even got to see the hidden blade in action! Very nice.

And finally, we have the gameplay that Sony showed us in their presentation. This features oceanic ship-based naval warfare, something not yet seen in Assassin's Creed, at least not on this magnitude. I don't have much else to say about it, so enjoy!
Assassin's Creed 3 is set for release on PS3 and Xbox 360 on the 30th October this year, with Wii U and PC versions to follow some time after.