I didn't get to play nearly as much as I wanted to, but I had a pretty great time with all of it.
I played a human elementalist, which was a pretty fun class to play. The game starts off right in the middle of an event - you have to fight off a centaur raid outside of Divinity's Reach. I felt there might have been a little more in the way of tutorial for the start, but it's possible I just sort of skipped over that because the controls are pretty standard and very similar to the layout of the first Guild Wars. I think I might have been a little lost if I hadn't already read so much about it.
The combat is extremely fun once you get your skills unlocked. Your first five skills are based on your weapon set, and I didn't feel like they were all just x damage. The first skill is usually something that's just spamable damage and it's the autoattack skill, but the others have some unique property to them - they'll apply specific debuffs or buffs or do very specific things. I ended up using a scepter with a dagger and had a nice mix of offensive and defensive skills. The elementalist can switch between attunements pretty much at will, so I had a lot of different skills to choose from, and attuning to a different element causes some immediate effect. A lot of my strong damage seemed to lie in my fire magic skills: I had two strong AoE spells, Dragon's Tooth and Phoenix, and the Phoenix hits foes on its way to the target, on its way back to you, and heals you when it returns. I had useful blinds in either Air or Earth attunement, and some strong knockdown and damage in Earth Attunement. Water was useful for some extra healing and slowing enemies, but my favorite combo was in Air: the two skills from my dagger were Ride the Lightning, which jumped me to my target and shocked them, and I'd follow it with Updraft, which would launch me and my foes backwards, and my foes would be knocked down when they landed.
Unlocking skills was a little annoying, because you have to unlock them per weapon type. So you start with the scepter and have your first skill, and then you have to unlock the others by fighting with the scepter. The first two skills to unlock were usually pretty quick, but it could take a lot longer for the last two. I found it irritating on the elementalist, because progress towards unlocking your next skill in an attunement was dependent on killing a foe while attuned to that element. So when I started unlocking my earth skills (it was the last attunement unlocked, you start with fire and water, then air, then earth), it took even longer because I had to keep reverting to other attunements to be effective in the area I was in. Once the skills were unlocked though, it was a lot of fun to switch between attunements on the fly depending on what I needed.
The combat itself is very visual and reactive, and success depends a lot more on not taking damage than being able to heal fast. A lot of foes were capable of taking out half my health with one hit in level appropriate areas. I didn't mind this because it forced me to play smarter with my skills and use them right when I needed them. Dodging at the right time helps a lot with not taking damage.
The death system is one of my favorite parts of the game. You don't die right away when you hit 0 health. You go into a downed state, where you can still fight, and if you manage to kill a foe, you rally and regain enough health to get back on your feet. If you don't rally or you don't heal yourself in time (which is difficult if a foe is still attacking you) or no one comes to revive you, you then become defeated and either respawn at a waypoint or wait for someone to revive you. The game encourages people to help revive each other by giving experience points as a reward for reviving other players.
I did feel like some of the events I played in could have scaled a little better to the number of people present. There were times where we had so many people helping that it didn't matter exactly what spells I cast as much as it did when I was alone or with only a few other people. However, when I was playing solo, I never felt like I was being overwhelmed. Yeah, if I did something stupid I would die, and even if I didn't it was still a challenge, but it was a fun challenge.
As per usual for Arenanet's standards, the game art is beautiful all around. I especially enjoyed seeing Divinity's Reach, the last human bastion in Tyria. I think my jaw actually dropped and I whispered "wow" when I first walked into the city. I do have to admit though, after playing the original guild wars for so long, it was really weird to actually be able to go inside buildings again. I forgot it was even a possibility when the storyline took me there!
I found that I liked exploring the personal story mode a lot more than just wandering around to find an event going on, but I did enjoy an event just springing up and getting distracted as I followed it off instead of going to the next point in the story. The game actually encourages that a lot, because if you just beeline through the personal story you'll very quickly fall out of pace with levels.
My one complaint was that when I did try to meet up with members of my guild and play, it was very scattered and disjointed. We just sort of ran around finding things, but we'd often get separated because we weren't all pursuing the same thing. If we had been working on, say, one person's personal story, it might have been a little easier, but aside from that, there's just so much going on that it was hard to feel like I was in an effective party with my guild.
Overall though, I felt like the game really encourages players to engage in whatever play style they like best. Almost everything I could have done had some reward for it. Participating in events yields a lot more rewards than just killing monsters, and I've heard of people getting so swept away by the events going on that they didn't even touch the personal story. Even exploring gave me experience - every time I entered a new area or found a new waypoint I got around 100-200 experience just for finding a new place. I didn't try the crafting system, but I bet that does too.
I think I only got a total of 8-10 hours playing in this weekend, but it was a lot of fun, and I can't wait for the next beta weekend. Definitely check it out if you can, and I'll try to take some screenshots next time. +)