Heroes is a MOBA in the style of DOTA or League of Legends. As for why it's awesome... Imagine Jim Raynor facing off against Diablo as Kerrigan fights Tyrael overhead and Nova throws down with Arthas. Then add explosions. Yeah. That was the Heroes trailer.
I got to play Heroes (which was five vs five, player vs player format) three times during the Con, which was a decent amount given that the line was typically between 30 and 90 minutes long at virtually all times and I still wanted to see other panels and play other demos. I played with friends each of the times, but mostly with friends we refer to as Thor and Loki.
In our first game, it took all of us a bit if time to get adjusted. The controls were fairly straightforward, but knowing when to do things was tricky. Similarly, we undervalued the objectives on the map. In this first instance they were tributes to the Raven Lord. We tried to get them when convenient, meaning the other team managed to get them and curse us semi-unopposed. That was a big deal as it meant we had no sustained push during the curse and had to retreat to our towers. We got the next curse and almost successfully pushed back to even things up, but our disorganization early on was ultimately our downfall.
We all stuck with the same characters in our three games (of which 2 had all three of us together and 1 had us with other teammates). Thor took Abathor from Heart of the Swarm (sidenote: we kept unintentionally calling Heroes "Heroes of the Swarm"), one of the toughest and coolest heroes. He was our support character, shielding us and slowing our enemies. Loki took Diablo and used the lord of terror's area of effect fireburst and his directed charge to great effect. He did a lot of our big damage. I ppayed Stitches, the Abomination from World of Warcraft. It took me a bit to master, but Stitches' hook was a great tool, allowing me to drag retreating heroes back to the jaws of death (Loki as Diablo, usually). Otherwise, I played Stitches as an anti-hero defense to hold objectives and towers.
We originally picked our heroes with minimal coordination, only really discussing our roles (Assassin, Support, and Warrior for Loki, Thor, and myself respectively), so it was a fortunate circumstance that they felt like they synergized extremely well. Abathor was perfect help for Stitches in the early game, providing extra survivability until I could get his levels up and choose health boosting talents. Later in the game, Abathor provided Diablo the extra health and regen to be able to operate solo for long periods. Diablo's charge and area of effect attacks also were great for cleaning up heroes pulled back or bunches up by Stitches.
We were able to use this to good effect in our second game as a team (I got one between these two with ither friends and Thor and Loki would get one later without me). Learning from the first game, we focused on the objective: finding dubloons to pay Blackheart to bombard our foes. As Stitches, I found myself playing around the spawning point of dubloon chests. Diablo and our other allies (Uther and Sonya) would range closer to the enemy towers, but I made sure we were the ones with dubloons.
This resulted in us buying Blackheart's bombardment three times to the other team's one. That alone was basically enough to earn the win. A few times, I was able to face down three heroes alone and hold them just long enough for Diablo to arrive, usually just after my death, to clean them up with his powerful attacks. Stitches' hook attack also was great for pulling foes off of objectives, forcing them to choose between fighting me or trying to run back to the objective with me breathing down their neck.
All in all, Heroes of the Storm was a great experience. All of my friends agreed that the fast paced games and relatively intuitive controls helped the game feel easy and quick. We're all signed up for the beta that is upcoming and can't wait to get back at it.