Brian Provinciano breaks it down
Retro City Rampage was in development for over six years, costing thousands of dollars and sleepless nights to develop. Brian Provinciano, the creator of the game, is finally getting a return on his investment. You may see some "exact" numbers elsewhere on the internet, but according to Brian, those figures aren't 100% accurate.
We do know that the game has moved about 100,000 units across the five platforms where it's currently available, with the most profits coming from PSN and PC. XBLA came in third, which comes as a disappointment. Provinciano reportedly would have "skipped" the platform if he knew then what he knows now.
WiiWare came in last place, which is also disappointing, but not all that surprising. According to Provinciano "It hasn't sold anywhere near 5,000 units on WiiWare. It has, in fact, sold only about 25% of the threshold". That means that until the game meets the mysterious WiiWare threshold, Brian wont get a penny from the WiiWare release. The good news is, if and when the game does meet the threshold, Brian will receive royalties to every unit of the game sold, including the pre-threshold sales.
If you've got a Wii or Wii U and nothing to play on it, why not get Retro City Rampage. It's $5 cheaper than on other platforms, and comes with special ROM version of the game that's not available on other consoles. Also, I'm in the game, which is pretty neat. All narcissism aside, it would be nice to see the WiiWare version at least hit the threshold so Brian could start to make back some of the $20K it cost to develop.