Gen 2 GSC Differences Collection for Simulator Implementation (help needed)

#52
No. It does not depend on +s, it looks at the actual resulting value. In most cases, it's pretty much the same as +s, however, there's a difference once you factor in the 999 cap.

So, once it crits, two calculations done: pre-stat upping and post stat upping.

So take a pokemon with 278 atk facing 258 def. Both stats reach 999 at +6. If it crits, 278 to 258 will do more, so stat ups are ignored.

However, pretend the pokemon had 258 atk and 278 def. Both stats hit 999 at +6 again. However, in this instance, 999 to 999 will do more damage than 258 to 278, so stat ups are applied.

+5 snorlax vs +5 snorlax, attack is 999 vs 798 def. 318 to 228 will do more in this case, so stat ups ignored.

Etc, etc.
I made a test on a link battle (again) to check if this is true, and found it isn't. Here's the test:

A Burned Machamp hitting a Ho-Oh with a CH Cross Chop. The damage was about 37%. Then, a Cursed Burned Machamp hitting a Ho-Oh with a CH Cross Chop. The damage was about 25%.

That's certainly not damage weighting because the diference is far too great. And if the theory was true, the Curse Machamp should damaged more.

I used a Burned Machamp because it lost half the attack, but the stat stage remains 0. When you Curse, the stat stage becomes +1, but the real attack is like -1 because of the Burn. In the first case, the stat stage of Machamp's Attack is the same of Ho-Oh's Defense, so Burn is ignored. In the second, the stat stage of Machamp's Attack is greater than Ho-Oh's Defense, so Burn is not ignored.

Here's how it really works:
If the stage stat of the attacking Pokémon (Attack or Special Attack, depending on the move) is lower or equal to the stage stat of the defending Pokémon (Defense or Special Defense, depending on the move), the stage stats are ignored on the damage calculation, as well as Reflect, Light Screen and Burn Status. Otherwise, they're not ignored.

An easier test can be made with Reflect. A +0 Atk Pokémon will do better damage on CH then a +1 Atk, if it hits a Pokémon behind Reflect.
 
#53
I made a test on a link battle (again) to check if this is true, and found it isn't. Here's the test:

A Burned Machamp hitting a Ho-Oh with a CH Cross Chop. The damage was about 37%. Then, a Cursed Burned Machamp hitting a Ho-Oh with a CH Cross Chop. The damage was about 25%.

That's certainly not damage weighting because the diference is far too great. And if the theory was true, the Curse Machamp should damaged more.

I used a Burned Machamp because it lost half the attack, but the stat stage remains 0. When you Curse, the stat stage becomes +1, but the real attack is like -1 because of the Burn. In the first case, the stat stage of Machamp's Attack is the same of Ho-Oh's Defense, so Burn is ignored. In the second, the stat stage of Machamp's Attack is greater than Ho-Oh's Defense, so Burn is not ignored.

Here's how it really works:
If the stage stat of the attacking Pokémon (Attack or Special Attack, depending on the move) is lower or equal to the stage stat of the defending Pokémon (Defense or Special Defense, depending on the move), the stage stats are ignored on the damage calculation, as well as Reflect, Light Screen and Burn Status. Otherwise, they're not ignored.

An easier test can be made with Reflect. A +0 Atk Pokémon will do better damage on CH then a +1 Atk, if it hits a Pokémon behind Reflect.
Wow. What weird mechanics.

Also, EW tested the defrost rate.
http://pastebin.com/Vr84Qpf0 <- number of turns per defrost

By reverse cumulating them, here are the curves:

10%:

20%:


10% really seems to be the defrost rate in GSC, and it matches NB's source (which says 25% for Adv, maybe it needs to be tested?)
 
#54
Yes, its 10%.

There are two very important things that should be added to the first post, IMO: How to determine the Unown letter, and how the Brightpowder works.
 
#55
Well, I really doubt that. I never knew that before, so I tested it on a link battle with two Pokémon Crystal cartridges, and that doesn't occur. The move fails even with a +5 Snorlax. This may occur in NBS, but not in-game (looks why I hate NBS?). I'll test it on GS after though.

EDIT: tested on Pokémon Silver now, and its the same.

EDIT 2: Powder Snow has 10% chance of freezing the target, as all the other Ice-type moves that can freeze (26/256 = 10,15625%). Don't trust on everything you see on Bulbapedia, specially when it comes to GSC.
What was the atk of the snorlax you tested with?