There no Walmart in UK, except its partnership or child company, ASDA which was sold just about a year ago. But I know that I would definately not buy a office laptop from the place, let alone an 'gaming' laptop. The place is good for household foods and goods, not for computers.
the problem is there are people who will buy pc from places that have no right selling them. These walmart laptops are relabelled laptops made with cheap parts to make as much profit as possible. You can't fault them when you have "respectable" OEM like Alienware doing this
So who do you trust for laptop? I don't know but its not Walmart or any shop you can buy anything other than PC parts in.
WE don't have Walmart in Australia either, or some other companies I don't miss (Cyberpower/Ibuypower come to mind) as consumer protections here ensure we get what we pay for. It probably cost more but its normally worth it.
having said that, I wonder if I can find that Alienware here.. close but not exactly. all here have 1kw psu, unclear about cooling though. Also, the USD1800 model is $3700 here so it better come with good cooling for Australia, but the motherboard looks bad anyway