So from my 6 hours game play so far here is what I have found:
Fireball Skill Tree: Going left, there are two nodes both labelled as Piercing Heat that do different things.
If you Despecialise Fireball after having points in Piercing Heat (the second one that allows for projectile piercing) and then add the same Fireball skill as a specialty, even if you don’t put points in that skill some of your projectiles appear to pierce through mobs. I’m not sure if this is because of an issue with the naming of the ability. Does not appear to apply to any other skill points on the tree for this or other spells (I have leveled Fireball and Electrocute and Glacier to 20 4 times over and this is the only one I find issue with).
Increased mana cost per point effects will not show on the mana cost of the abilities when you hover over them on your skill bar.
If you have multiple characters, gaining gold on one appears to randomly reset gold on the other character (unless there is some hidden way that gold is added to the Stash?)
Passive Skill Tree, once you have entered 30 points into one quarter as the hover tool tip says, it does not cap the points not does it change the hover text.
When Exiting Game to Character Selection in fullscreen mode, the game occasionally locks up and has to be fore exited.