In the first Castlevania game, there are secret treasures all over the place, some collectible, and some not. Most of them require you to duck in a specific place to make them appear, but there are a few that are a little more finicky.

For instance, in Area 2 (technically called 'Stage 5') you come across this innocent looking ledge.

Most people that I see play this game jump up on it and continue on. But if you don't want to be like most people, you could just stand on the blocks for a few seconds. Which will reveal...

A secret treasure chest (worth 2000 points)!

There are a few more which require standing still to make appear, but we'll talk about them another day.