Must be done in one playthrough as your counter at the top of the screen must show a number 50 or higher.
That being said, the good news is that it's entirely possible to get this going from Zone 1 to Zone 9. Defeating champions (enemies with a star above their head) will drop a predetermined amount of candles. Ensure you collect them all after each kill and you will surpass the 50 needed before reaching the end of Zone 9.
You can technically do enough damage to get all the way to Zone 10 without any upgrades or opening chests and changing/adding additional weapons. Just let the game do it's thing and be sure to grab every candle and this achievement is yours!