...leading to a giveaway, which is over.

I'll add the winner in steam and give him the key.
The Giveaway starts Friday, 4th of October at 15:00 GMT+2 and ends Monday, 7th of October at 15:00 GMT+2.

So let the treasure hunt begin: First Breadcrumb

Answers

1.1 'John Chambers' Famous Hollywood make-up artist, who created the masks for "Planet of the Apes"
1.2 'Tony Montana' Quote from the movie "Scarface"
1.3 'Reynald de Chatillon' Quote from the movie "Kingdom of Heaven"
1.4 'Johann Wolfgang von Goethe' Famous german author, his last words.
1.5 'Cats' Quote from the videogame "Zero Wing", a famous internet meme.
1.6 'Hansel and Gretel' A reference to the fairy tale "Hansel and Gretel" written by the Grimm brothers.
1.7 'paradox' or 'liar paradox' Liar paradox
1.8 'Battle of Sedan' The date of a battle within the Franco-Prussian War, written in Latin numbers.

[2] '874929981' The number is hidden at the end of the image source-code.
[3] '744251498' An MD5 hash wich can be decrypted.
[4] '619664830' The number got encrypted to binary code, which got encrypted to morse code.
[5] '369640174' The number is hidden on the image.
[6] '636590363' The answer is part of the number pi. Tiger hint: Life of Pi
[7] '023421314' Just trial and error. The 0 is the first character in the title.
[8] '191246771' The number got encrypted to ASCII decimal character.
[9] 'VeZ6nRgq' The answer is hidden in a txt-file, which got archived and combined with the image-file.

10.1 'air' 1st child: fire; 2nd child: earth; 3rd child: water - The four elements.
10.2 'Tower of Babel' A story in the old testament in which God confuses the men by giving them different languages.
10.3 'chicken' or 'egg' Just for fun :P

Hints
Here I'll post hints and updates on the puzzle:
-1.7 got updated.
-Ordered the breadcrumbs by number ( [1],[2]...)
-1.7 got updated again...
-Added a mirror for [5] as user mentioned display problems
-[6] got updated
-Added a second possible answer to 1.7
-Read me
Because of problems with the old hoster, I moved the puzzle to new one.
The old links are not working anymore, but the answers are the same.
Look at the first puzzle for the new link/hoster.

[1] Hints on the puzzle site.
[2] The answer is in the picture.
[3] It's commonly used to check file integrity.
[4] It's double encrypted.
[5] Look closer.
[6] What Tiger?
[6] It's a very big number.
[7] Want a hint? Trial and error :D
[8] It has absolutely nothing to do with math.
[9] The image seems me to be too heavily packed.
[9] Remember [4]?
[10.1] The answer is elementary.
[10.2] It helps if you've read the bible.
[10.3] No comment on that...

Still don't get it? There are many hints spoiled by the solvers and me in this thread.
Or check those two pages: zelgh magic guide to basic sg puzzling and Free No. 1 Tool.