Never played this before and just finished Act 1 with a Seer (Dream) on my second attempt. First attempt was with a Warrior/Rogue build and stuffed it up. Deleted the character and tried again with a different build. Haven't died yet. I know I can get a second mastery but not sure which one to go with or just use the one mastery. I'm mainly using:
Left mouse button: basic attack (now Psionic Touch. I don't know if it's doing anything)
Right mouse button: Phantom Strike with Dream Stealer (both maxed) [This is like a teleport bomb killing up to 6 enemies]
Skill Quickbar: Distort Reality (helpful to kill groups of enemies and is like a second bomb going off)
Every level up I alternate between:
1 HP and 1 STR
1 HP and 1 Dex
Skills:
1 Level (Up to ~18) [adds HP, STR, DEX, INT]
1 Phantom Strike
1 Dream Stealer
Then:
2 Distort Reality
1 Psionic Touch
Not really sure if I'm playing it right but I'm finding the increase in STR (physical damage) and DEX (offensive/defensive) working well and no need to put anything in INT as leveling up the Skill Mastery already puts points in INT. But I'm finding this mastery really OP with a sword + shield build.
I will say it helps to read the manual before playing this game as I just figured out now how to put relic pieces together and putting them on weapons/armor after I've finished Act 1.