Pokemon G/S/C - Damage Calculation with Critical Hits
26You would naturally think that having a stat level advantage over your opponent will always translate to higher damage output, right?
Well, that's not always true! When critical hits are combined with stat level modifications, screens, and/or burn, anything can happen...
If a critical hit occurs:
(1) Stat level modifications are ignored if they are neutral to or favour the defender. For example, if the attacker had used Swords Dance before critting with a physical attack, the Swords Dance boost would be applied. However, if, in addition, the defender's Defense level had been +2 or higher, none of the two stat level modifications (attacker's attack and defender's defense) would've been applied.
(2) Reflect and Light Screen defensive boosts are only ignored if stat level modifications were also ignored as a result of (1). This includes the scenario where no stat level modifications exist in attacker's [special] attack or in defender's [special] defense.
(3) If the attacker is burned, stat level modifications are always ignored. The attack drop from the burn is only applied when attacker's attack level is higher than defender's defense level
A particular case of (2) is shown in the first part of the video and a particular case of (3) is shown in the second part of the video.