How is it possible to claim giveaways, when codes were posted weeks ago? Once I tried to catch twitter giveaways, but as soon a code is posted, army of bots immediately grab it and use it. I even think there is a script, that check Duelbits twitter account and make automatic claims.
I am amazed by amounts you have managed to claim. I am more used to seeing cents in such giveaways, and only once saw xmas giftbox giveaway, that gave such huge prizes.
The codes that Bitcoinhunt3r validated were from Telegram and there are some wagering requirements before you can claim them. Minimum wager requirement was 1500$, which is probably why these codes can still be validated after being posted more than 1 month ago. Codes on Twitter are always without requirements.