First of all, thanks to everyone for the kind words you've posted on all the giveaways, I didn't answer but I've read them all.

I'm very happy that 5 out of 6 giveaways have been won by those that solved the whole puzzle, their hard work has been rewarded. But now, let's go on to the

SOLUTION:

• each of the giveaways linked down here had in its description a link to a song on Souncloud. Each song had a one-character title. Sorting the titles in the order I specified on each description gives you the first link ( lFG8S - Hitman Blood Money );

• the second step was a itstoohard quiz in which you had to say the title of the songs linked for the previous step, or the show they were featured in. The solutions were:

  1. Tank/Cowboy bebop
  2. Sorairo Days/Tengen Toppa Gurren Lagann
  3. Tell me why/Berserk
  4. Zankoku na tenshi no these/Evangelion (Here I forgot to put the full title of the show, sorry to those that were slowed down by my mistake)
  5. The world/Death note
• anyway the quiz was a red herring. It rewarded with five Dota 2 keys -- I'd really like to know if somebody took them, just one of those who got there gave me any kind of feedback about them. The link was hidden in the source of the itstoohard puzzle. ( hsvEa - Just Cause 2 );
• 30 trollfaces, numbered from 1 to 29, with the last one having 42 as its title instead of 30. The hint was in the giveaway description, referencing LOST. On the cheek of every face there were some pixels added by me. Those on the faces numbered 4, 8, 15, 16 and 23 spelled out, in Braille, the last step of the puzzle ( nXIBF - Deus Ex: Human Revolution Augmented Edition ). The 42 image? It was just me trolling a little :P
• as a consolation prize for those that already had DX I put on the last step a giveaway for The Missing Link;
• the hidden giveaways were buried in the comments of Hitman ( 3nTZp - Metro 2033 ) and Just Cause 2 ( Gk7Iz - Warhammer 40k: Space Marine )

I hope you had fun with this puzzle :) Congratulations to the winners, and happy birthday to me! :P

Hint #1: the links down here? Totally relevant.
Hint #2: the first step is as easy as doing 1+1+1+1+1
Hint #3: for the newcomers stuck at the quiz: you may want to check the giveaway you came from, I've put the hints for the quiz in there.
Hint #4: modified something to help you with the last puzzle.

Solvers:

bobofatt (also got both secrets)
dehill
Cymbaline
snake49
Ishmaeel (also got both secrets)
pamput (also got both secrets)
ErnisDy (also got both secrets)

I'll leave
these links
right here.
Maybe
you'll need them