Hold on, this is not a DRM-free book bundle like Humble normally does. I'm gonna have to look into what it being on Kobo means to me.
EDIT: US customers only. Humble has gone to shit.
Update: I bought the bundle anyway, and it's fucking
obnoxious to use this on anything but Kobo's site/device.
I haven't even tried transferring this to my Kindle, yet, but so far I've had to download Adobe Digital Editions, create an Adobe account, authorize my computer, then use the downloaded file from Kobo to get ADE to then download the actual book, which is still laden with DRM. I'm not sure what it'll take to get that still DRMed EPUB file to be read by my Kindle. So, fuck it, I'll find an extension for Calibre that will let me read the books I just bought without having to jump through their hoops.
EDIT: Other janky shit about the process. The redemption code from Humble for Kobo isn't a product key, it's a weird discount code. You follow a link, and then have to click ADD to all of the books, then enter the code to get the books for free.
When you're downloading the file that tells Adobe Digital Editions what book it needs to download for you, the default file name from Kobo is just URLLink.ascm for every single file. You have to rename them by hand.
Most of the books don't have a proper thumbnail for the cover in ADE. Only ten of 38 do, and not all of those with crappy generic thumbnails are in the same style.
This is a horrible user experience.