I tried to start with basics and build up to some consistent formulas, but gave up after a few data points (including these below). All Explore 12, no skull reduction.
Talent: Lightning Strike
Trait: Chaotic (Sin’s Harvest)
Exhibit A:
Simple 4-match with 1 doomskull.
Attack 59, damage done 64.
Question 1: should this have been 65 (59 base, +1 for 4-match, +5 for doom), or does critical hit only start from 5+?
Exhibit B:
No lightning strike, -2 skill points (life) already taken into account.
Total damage done = 79
I expected 76 (59 base, +10 for 2 skulls, +7 from match explosion)
Exhibit C (immediately following from the above after explosions cleared):
Lightning strike at row 3 column 2
Total damage done = 101
I expected 82 (59 base, +10 for 2 doomskulls, +2 from 5-match, +5 from match explosion, +6 from lightning strike explosion)
Exhibit D:
No lightning strike, -2 skill points (life) already taken into account.
Total damage done = 112
I expected 102 (59 base, +15 for 2 doomskulls, +2 from 5-match, +26 from match explosion)
To my untrained eyes, it looks like there is some code that causes skulls/doomskulls to be counted multiple times. With enough data, one might work it out (there might be a difference between L-shaped 5 match and straight 5-match?, there might be a difference between where the skulls are placed in a 4/5-match?). But I’ve already sunk too much time into this.
(I do have videos recorded with GoW at 0.5x, but just trust me on the data above)