In HTFA 1, you can recover health by picking up hearts. One heart adds one health to the counter. Even though you start with three points of health either from the start of the game or after dying, you can add more by picking up more hearts (maximum health is around 16, though).
In HTFA 5, you're back into collecting hearts to recover your health, only this time, the heart's sprite is smaller and colored pink. Unlike the previous games, collecting these hearts recovers 2 health points.
Even though the game isn't finished yet, the beta versions show that the recovery item is a red heart, which is bigger than the pink heart in the previous two games. It re-fills two sections of the health bar, much like how the pink hearts can recover two health points.
Like most HTFA games, HTF Origins features hearts as recovery items. The heart's sprite is larger than the pink hearts in HTFA 5 and 6, but is smaller compared to the first HTFA and the seventh HTFA. Like the more recent HTFA games, these hearts recover your health by two points each.
This game also features hearts as recovery items. Due to color limitations (as an attempt at "complete retraux"), the heart item can usually blend well with the background. Much like the older HTFA games, picking up a heart only restores one health point (seeing that the tree friends in this game have five health points in total, this is justified).
Even though it's a recent HTFA game at the time, the health item's sprite is re-used from HTFA 5 and 6, and it gives the same amount of health recovered when picked up (two sections of the health gauge).
This game also features hearts as recovery items. Similar to HTFA 5, 6 and Land, a heart in this game recovers two health points. The heart's graphic depicts a big red heart, which is actually taken from the frame used in Giggles's Valentine Smoochie.