Neko Atsume is a game where you can raise cats and earn fish, which can be reinvested into buying goodies and better food to attract more cats. Sudoneko lets you ruin the game for yourself. It does this by making you so rich with fish that you could probably put what's left in a retirement account and retire in thirty years, rich and cat-happy.
Go to your Android or iPhone Wi-Fi settings and select your network.
Find your advanced settings and enable the proxy. On Android, this is done by setting the proxy to "Manual." Set the settings as follows:
Open Neko Atsume and go to the Connect Menu. Tap on Input Password, and on the menu that appears, enter in any gibberish that you like.
You'll get a ton of fish, enough to buy everything in the game. This can only be done once a day, as the game keeps track of which day's tokens you've used.
Once you do this, go back and turn the system proxy back off.