A mere day has passed since Fallout Shelter's release on Android and already hackers have found ways to cheat in the game, messing up its online leaderboards.
Unlike the iOS, which remains difficult to hack (unless you jailbreak the operating system), Android games lack all of the security you might expect from a mobile platform and are wide open to hackers screwing up the leaderboards with their shenanigans. Fallout Shelter is no exception, and cheaters have found ways to inflate their personal scores to screw up the leaderboard.
Screenshots posted on the /r/foshelter subreddit show the extent of cheaters' efforts to ruin the leaderboards, achieving scores higher than anybody else in happiness and overall score.
If you plan on participating on an even playing field, I'd recommend just sticking to the iOS version of the game.