If the show had avoided using dozens of ridiculously pathetic immature clown characters and stuck to characters who, on the whole, respond normally to the situations they find themselves in then I'd give the show an extra star. The lead character is utterly pathetic. God knows how he made it to adulthood, let alone get married and have child. A child I might add, whom at 10 years of age is about 5 years more mature than her deadloss father. The man is an utter waste of space. One critical disappointment with the show is the lead character isn't killed in the first 30mins of episode 1.
Essentially, the premise of the story is whether it's better to live in normal society with alot of debt or gamble your life for the slim chance of getting your debt paid. Of course, it's all a bit silly and if I'm honest the Japanese have made far better movies on a similar premise. The Japanese tend to use 18-25 year olds, who are rarely pathetic characters. Does it make for a better watch? I'd say so. That said, this is far more entertaining than the Hunger games
Does the show have a message? I'd say the most obvious one is don't gamble, no matter how desperate you are or how bad life gets. Gambling is not the answer. The show could've made that point without the gore & violence but then it'd just be like any other drama and no-one would be paying it much attention.