Wasn't there a glitch for it at some point, though? That you could "kill" the kids an infinite number of times because they wouldn't die? That's how someone advised me to level up...
100% Arcade/WP/Win8  | 100% Retail  | 100% Xbox One 
First achievement unlocked in Fall 2009 | 100k on April 05, 2016
Sig courtesy of DethHolly.