The puzzle image is random, so if you get one you've already assembled, just reload to grab another one.
Puzzle images are manga art for now. They will be replaced with SMCrystal art as it becomes available.
There's some chance involved in playing these... you may not always get the best prize! Don't get discouraged, just try again the next week and see how you do!
Pick(pocket) a Boy the Shitennou have been naughty - take their stuff!
In addition to the weekly games, there are some fun forum activities to participate in, which will allow you to interact more with other players. :) These games are completely optional (well, I guess all TCG games are!), but you will miss out on extra cards if you choose not to participate.
Oh, yeah, I want to make some other random games too. :D The thing about these is that while they update kind of randomly, all the older rounds of each game will always be available! So if you happen to miss one, or join later on, you can still play them all!