I also played this a bit over the weekend. It reminds me a lot like Hellgate: London - but not in a bad way! More like, if the Hellgate writers were not nearly as incoherent and if the graphics were updated to modern standards… it is more like I remember Hellgate playing back in the day rather than how it actually played (I found it did not age well, when it was re-released on steam recently). The starting hub and initial environments reminded me a LOT of the starting Hellgate maps.
A few annoying things: character progression is kept in multiplayer, but not the story progression. So, be prepared to replay plot if you are not hosting. Also, although billed as drop-in, drop-out, you will not be able to join the party and actually play until everyone reaches a bonfire (or everyone dies). This means you might be waiting for several minutes after joining a game before you can actually play… If this is not true, I sure would like to know!
Class selection heavily influences game play in the first part of the game, but it looks like as you level you can get the equipment and skills of other classes (so moving from a scrapper to sniper is perfectly doable, just the starting equipment will tend to force the role initially).
Boss fights are definitely tricky… It was frustrating solo - the bosses + all of adds were very hard for me to handle by myself. However duo was perfectly playable for me, and turned the boss fights from impossible tasks… getting one or two shotted over and over again… to something doable (given a few retries to learn the area, boss patterns, etc).
The rhythm of the game is: leave the hub to enter main world (this might be a fixed map, I am not sure yet) - find a dungeon entrance, then fight though the randomly generated dungeon, then a boss fight (selected from a number of possible bosses for each area). Defeating bosses will unlock skills and crafting materials.
It feels like a combination of Hellgate and maybe the Chalice dungeons from Bloodborne. So far, a promising games - not really a looter shooter, as most equipment so far is either crafted or simply upgraded (+1 shotgun, +2 shotgun…). There are unique items that can be found on the maps, like rings providing +crit for x seconds on monster kill and so forth.