This is the highest number of likes required for an achievement. You'll unlock other achievements on the way to this - the fastest method I found was to:
1. Sign in with a second controller
2. Press
on both controllers to enable dual mode and hold
on each controller to sign in a third and fourth player
3. Start and complete a level
4. When it pops up saying "Stage complete", click
and
on both controllers as many times as possible (you can get 130+ likes per level). You'll know you've done it right if there are already 40+ votes when the players' names appear.
5. Repeat until this and other related likes achievements pop (even when the number of hearts caps at 999, the numbers of votes is still tracked).