Kirby Air Ride still has my favorite unlock system ever, it was a huge grid of hidden achievements and when you completed one it would reveal the four adjacent achievements. You'd get the first few by complete accident because there were freebies like "finish 1 race" "finish 1 race on X vehicle" and then your unlocks would spread outward across the board with a nice satisfying SLAM SLAM SLAM revealing them one-by-one after each race.
Some of the Smash Bros games had the same system, with the added mechanic that you also unlocked a small number of hammers that could unlock squares without having gotten the achievement for it
Kirby Air Ride still has my favorite unlock system ever, it was a huge grid of hidden achievements and when you completed one it would reveal the four adjacent achievements. You'd get the first few by complete accident because there were freebies like "finish 1 race" "finish 1 race on X vehicle" and then your unlocks would spread outward across the board with a nice satisfying SLAM SLAM SLAM revealing them one-by-one after each race.
Some of the Smash Bros games had the same system, with the added mechanic that you also unlocked a small number of hammers that could unlock squares without having gotten the achievement for it
That's actually from Air Ride too! 5 of the squares rewarded purple checks you could use to unlock another square for free
Oh neat