The lights are on
We all remember when the DS was popular. When virtual was virtuoso, when retro rocked, and-wait for it- when glitches were glamorous. Half of its games had "freeze moments" seemingly built into them. Take the Bloons Series. Aside from copying Kingdom Rush, it's a great PC tower defense series. Now look at BTD4 on DS. Every 7 or so runs, it starts glitching and letting you survive Bloons you missed. And every game around Level 75, the levels start freezing.
Point being, this is a great, do-not-return-it-until-you-quit-your-files-or-beat-them kind of game. If it malfunctions once, don't trash it.