i don’t know if this is just an “error” happening for me/on my end
but for some reason this game+its “claim page”/key entry on account, does not show up after closing the first time despite “being claimed”
meaning unless written down or something, it doesn’t appear like you can “get to it later”/redeem as you wish when convenient… 
don’t know if it’s just me (but it’s the only game/key/page that has behaved like this on my browser),
but i had to “backtrack” through my previous visited pages to get it up again,
so maybe, (to those that do actually want the game but might not be able to redeem it the moment you unlock it), a “just in case warning”; don’t close the claim/unlock page, either redeem it immediately or write the key down, because doesn’t look like you’ll be able to get back to it later and click/redeem again then… atm… -will keep an eye out if it appears available on my account page again/later, and note here if it changes
Thank you so much!
BUT, if my maths are good, I believe I might just get it, I have two stamps as of right now, I don’t exactly know when will it end, but I believe I might just get it?
Yeah, it’s not showing up in my account either after claiming. Maybe this is because, unlike Humble’s other free game giveaways, there is no actual checkout process?
Definitely follow @Gnuffi’s advice and copy the key immediately after claiming.
I think you have just enough days, so good luck!
@Gnuffi and @DanosaurJr, noted, will definitely keep track of the key when first displayed. 
they ran out of keys…
Did they post a statement saying as much?
yes when trying to claim the key; they say they’ll get some more sometime
and the weird thing is, though it says i “claimed” it, it’s not in my humble library
As Gnuffi and DanosaurJr noted above the only notification you get of the key is the actual page…I left the page open last night and waited for an email/checked my key page with no result. I’m actually glad that I used the redeem button straight away.
I hit the redeem button straight away man; that’s when it said there were no keys left and that they would get new ones… sometime… and now when i go on that page it says “claimed” but it’s not in my library so i guess im never getting that key lol
Well they used to be good for their word. My humble account got hacked and They worked with me for over a week. I had to go through all my stuff and supply the invoice no(or some number) for each game and they gave me a new key. I did lost all my dups which sucked but what the hay…I got the game keys back.
So if they say a key is coming, I think that are good for it.
Really strange indeed. After seeing this I tried to claim my key (I gathered the points an hour ago and left the page open without clicking the redeem button) and that’s what I got just now:
and this:
I don’t doubt they will fix this, but when though… Hopefully soon.
lol
I got the same issue…
I know some people were not able to find their key after they exited the page with the key, I wonder if we will ever get our key…
I can still access the key page via purchases tab in the account drop down. No idea why disappeared for some people 
Not sure, it does not show up for me in the keys or purchases pages… I will just wait and see.
For those waiting for the key, I finally got mine, yay~!
They seem to also have added a DRM free download of the game
yup, got mine too, thx
Do they notify you by email?