There are a number of collectable items in the game, but only three of them are counted into the score:
Other collectable items are:
Any collectable can be picked up by touching it: including mid-fall.
Single coin gives 10 score points.
Gems can be one of four types, differenciated by the amount of score it adds.
Depending on gem type, it gives 100, 200, 300 or 400 score points.
One collected key gives 1000 score points.
Learn more about the scoring system here.
Pill item makes your movement two times slower and triggers distracting visual effect. This effect lasts for 20 seconds. If during the effect of a Pill, another Pill is collected, effect is getting prolongated by another 20 seconds.
For timed levels, during its active phase, it speeds up time counter by a factor of 2.
This item only appears in timed levels. It reverts remaining time by substracting it from the initial level time and setting the result as a current counter.
So if you started timed level and 3 seconds later picked up an Hourglass, three seconds after that level will time-out.