Solution to Logic - Reasoning:
GA code you were looking for was http://www.steamgifts.com/giveaway/9KZOf/blackguards . Only 4 GA codes meet all rules set in Entry GA. 9K[AZ]O[cf] so you had only a total of 4 codes to check: 9KAOc, 9KAOf, 9KZOc and 9KZOf.
There were multiple ways and routes to get solution plus some rules were totally not necessary and only there to let you check with multiple sources if what you got is right. You can see a lot of discussion over the puzzle and solutions in Blackguards GA linked above, so below I will just present you one of possible solutions.

1. From #3 we know there is only one NUMBER in GA code.
2. Rule #8 tells us NUMBER is either 1st or last character of GA code.
3. Rule #15 says about alphabetic position of last character in GA code mreaning it must be alphabet letter and it cannot be number, thus NUMBER must be 1st character of GA code and 4 next characters are letters.
4. Rule #13 tells us that not all letters are the case mase, aka we have lower and upper case letters in GA code.
5. Rules #5+#7 tell us that last letter in GA code (and we already know it will be on 5th position) must be lower case.
6. Rule #6 tells us that 1st three etters must be the same case. since we know there are both lower and upper case letters in GA code and 5th character is lower case it means letters on positions 2,3,4 bust all be upper case.
7. From #14 we learn that 4th letter is often confused with number in GA codes. We can think of several letters like that - O confused with 0, l (lower case L), I (capital i) both confused with 1, b confused with 6.
8. So it cannot be l (lower case L) or b, because they are lower case. 4th character can be O or I (upper case i).
9. I is 9th letter of alphabet, O is 15th.
10. From #4 we can find possible corresponding letters for 2nd position in GA. I->D or O->K.
11. Using #12 we check these letters. for D it would mean that 4=2+NUMBER, NUMBER would be 2, and as #11 tells us NUMBER is not Prime it cannot be 2. So it must be O, K combination.
12. Using #12 again knowing it's K we get 11=2+NUMBER. So we know the NUMBER is 9.
13. From #15 we get that alphabetic position of last letter is a single-digit number (1,2,3,4,5,6,7,8,9), and NUMBER (9) are two different numbers divisible by the same number β=/=1 (without remainder). We can divide 9 without remainder by 1, 3 and 9. β=/=1 and these are 2 dfifferent numbers, so β=3. What other numbers 1-8 are divisible by 3? Only 3 qand 6. aka last letter in GA code is either 3rd or 6th letter of alphabet, so it's c or f.
14. Let us look on our GA code now: 9K?O[cf].
15. Rule #9 tell us that one of the letters is either first or last letter in alphabet, so a or z. We don't have a nor z in GA code yet so it must be on 3rd position. We also know it must be upper case. This way we ended up with GA code 9K[AZ]O[cf] which gives us only 4 possible solutions and which we can easilly bruteforce :>

Solution links for Science Sucks! added.
References for the second puzzle:
Q1. Neverwinter Nights 2.
Q2. Doctor Who.
Q3. Discworld/myth of the World Turtle.
Q4. Harry Potter.
Q5. The Elder Scrolls IV: Oblivion.
Q6. Harry Potter (Gamp's Law of Elemental Transfiguration)
Q7. Myth of the birth of Aphrodite/Venus.
Q8. Star Wars.
Q9. Magicka's magicks.

9 of my giveaways have been sent. The winner of the 10th hasn't activated a gift they won yesterday, so I'll wait a few days to see if that changes.

Solution links for Climate section are added.
9 out of 10 prizes are sent to winners.

What a fabulous event!! Some won a boatload of games, friendships were made and the collaboration was amazing!!

Bump for only 7 games of mine awaiting feedback. We are so close to 1K comments!

Claps
Job well done, Jeff, Everybody.

Got 7 games from this wonderful event!!
Thanks a lot Jeff and all the guys (and gals) who have contributed the puzzles.. ;)