Mario’s Picross is a fun, addictive puzzler… that might steal your soul.

If you’re a Club Nintendo member with at least 100 coins and a 3DS, you need to know that you only have one day left to grab a free copy Mario’s Picross. Seriously, if you even sort of like puzzle games, you need to give this game a shot. It’s kind of like Sudoku, only easier and more fun. When you’re done with a round of Sudoku all you have is a bunch of boxes with numbers scrawled in them and regret for being tricked into doing math for hours. When you’re done with a round of Picross, you have a picture of a doggie! Or a boat! You’ve also lost like four hours of sleep because you kept telling yourself “I’ll do just one more.”

I love that Club Nintendo is giving away Virtual Console/Wii Ware/eShop titles as rewards. Doodads and trinkets with Nintendo characters on them are fun enough, but I love Nintendo because they make great games, so of course I want free games. I was willing to take a gamble on Mario’s Picross because it seemed like a neat idea for a puzzle game, and I was curious about this odd, obscure little title. I had completely forgotten the game had ever even existed that until I saw it available as a Club Nintendo reward earlier this month. But of course, the biggest reason why I grabbed Picross is because it didn’t cost me anything. And I’m so glad I did: I just got it a couple nights ago and I’ve already dumped hours into the thing. It’s insane.

Mario’s Picross has a great tutorial for newcomers, and features a whopping 256 puzzles. Food, animals, vehicles, Mario characters, appliances, you never know what you’ll chisel out a picture of next, and the gradual reveal is a major fun factor. Knocking out squares to make a picture may not sound as intense as Tetris‘ falling blocks or Bust-a-Move’s advancing wall of bubbles, but Mario’s Picross does raise the stakes. Each puzzle has a 30 minute time-limit, and every time you make a mistake, you are penalized 2 minutes, then 4 minutes, then 8 minutes. There’s a special thrill to finishing a puzzle with 3 seconds left on the clock.

What started out as “hey it’s free, I’ll give it a shot” has quickly become a minor obsession for me. I caught myself browsing Amazon for Picross DS and Picross 3D, and I’m not even close to being done with the Picross game I just got. Picross DS is a critically acclaimed spiritual follow-up to Mario’s Picross, both from developer Jupiter. Picross 3D is a crazy, 3-dimensional reimagining of the game from HAL Laboratory that sounds fascinating. I take a little comfort in knowing I’m not alone in my new-found Picross-fueled madness: while Mario’s Picross was a flop in the U.S. and Europe, it was a smash in Japan, spawning sequels for Game Boy and Super Famicom that never made it to the international market.

So you’ve got one day left to grab this forgotten gem. After that, Club Nintendo will roll out another handful of free games. Here’s hoping that line-up includes another diamond in the rough like Mario’s Picross.