Lollipop Chainsaw

The score to beat for stage 3 is a whopping 294,900.

Stage 1 and Stage 3 were the hardest for me to beat "dad's score" (which I was able to do on Normal or higher on every other level), but here's how I finally accomplished it. I mainly used the spin-on-the-ground combo (A then X's) after waiting for as many zombies as possible to gather around me. I also had to do it on Easy, since they're easier to kill with that combo in Easy mode. Every time there were 3 or more zombies, I attemped this. The goal is as many sparkle hunting bonuses as possible throughout the level. It didn't always work, but it was enough to put me over the top when the end-level bonuses were added.

(Just barely, though; I ended the chapter with a total score with bonuses of just over 300,000, and that was without a penalty for dying/continuing -- which would have subtracted 5000 for each one.)

Beyond that, just do everything you can. Don't die/restart if you can help it (which you easily can, on easy), get all the QTE's, kill all the horses and cows, kill all the chickens for +100 each, etc. Near the end, before the final boss, you'll get 3 waves of 8, 16, and 32 zombies, which helps rack up a few final sparkle hunting bonuses.

Note that even if you manage to beat the score before finishing the level, the achievement doesn't unlock until you do, once the scoreboard appears and bonsuses/penalties are added.

Update: As some have pointed out the Nick Shake is helpful here too. Use it when possible, during a break in the action, to rack up more medals for end-level bonuses.

Good luck!

Have to agree that this along with stage 1 are probably the most challenging Dad scores to beat. In addition to the great guide provided by Wyndo, it's worth keeping in mind that you can get big points from the trampoline section in this level too.

After the first trippy sequence, you'll come to an area with a waiting headless corpse. Behind the corpse, down an alley, is a trampoline. When you hit it you'll have to first nail a section of QTEs for jumping on zombies that spawn. Once you've popped all the zombie heads and bounced a second time you'll be given a cheerleading QTE. Rapidly pausing and unpausing the game will allow you to anticipate and nail way more of the cheerleading prompts than you would normally be able to hit. Each correct button press increases the score reward too, so one long string of can be worth 30,000 points (or more if you're quick enough) for this one small section.