TLDR: Producct is great, people who open the boxes or steal parts are just the worst.
4 stars because it is difficult to find the blind boxes unopened in any of the 4 stores within 15 miles of my home. Not the fault of Lego. 100% the fault of disrespectful people. Also the fault of Walmart management or loss prevention employees not keeping an eye on the feed from the security cameras.
I enjoy the concept of the blind box gamble, it is fun. What I do not enjoy is seing people outright stealing parts or making sure that they were getting the minifig they wanted by opening the boxes in the casepack right there at the display, and leaving them open/ruined/mangled/incomplete on the shelf, back in the casepack mixed with unopened boxes, or behind the casepack on the back of the shelf. People need to have some respect and do better. It really isn't that difficult to download and use one of the minifigure blind box scanning apps, like Minifigscan, to read the QR codes on the bottom of the boxes to know what is inside.
Walmart needs to do better by either (a) having these items behind locked glass for protection, (b) have them in a more public space like a front endcap so to discourage theft or destruction, or (c) place them in one of the "camera monitoring areas (like the vitamins and personal care aisles have) so that a manager or the loss prevention/security employees can get to the offending person before they destroy all of the stock on the shelf and ruin the experience for the rest of us. The only way you are truly guaranteed to get unopened boxes is if you order them online...
As for the actual product - Series 29 has a good variety of characters, with only 2 of the 12 that I was indifferent to, whoch os a mich smaller number than the ones I dod not like from Series 27 or 28. The Monster Hunter was well designed with good detail, the Boba Cup Fan was cute, the Bionicle Cosplayer was a nice throwback, and the Mysterious Ronin reminds me of the Lego Ninjago characters (not sure if that was also supposed to be a throwback).
Good luck finding them in store and happy hunting for all 12 to complete your series set!