Rock Columns
Rock columns may reveal helpful items inside, if you shoot and break them with your straw gun. These items may include normal notes or red sunshines. In certain situations, these columns may be used to fetch items in "hard to reach" places. Be aware that some enemies like to disguise themselves as "rock columns".
 
Sunshine
Red Sunshines restore your entire HP (health). They can appear just about anywhere in the game. Look for hidden suns inside rock columns, through hidden walls or even in thin air! Raisins love sun!
 
Rasinette
These "Kid Icarus" like items act as extra lives. Look for them through hidden walls or in hard to reach places. Sometimes you'll see one on the other side of a wall while you're exploring the level. Always try and have a good sense of direction while navigating the levels. Being able to come back to these "life savers" can come in handy in the late stages of the game. I've always found Rasinettes to be the most useful in the Grape Vine stage against the "Foot Boss".
 
Invincibility Badge
For a very shot period of time, your raisin will be invulnerable to enemy fire, if you find one of these badges in the game. I don't suggest running rampantly through a room if you find and use this item. You may take more hits after your shield runs out than you would if you paced yourself through the room in a controlled fashion...
 
Normal Note
Look for these stolen notes scattered throughout each level. These simply act as bonus points relative to your final score. Although there is a rumor that finding all the notes in the entire game, will reveal a hidden ending...
 
Golden Note
At the end of each level, you're awarded a "Golden Note" once you've defeated the stage boss (Yeahhh!). Collect all four so you can unlock the penthouse of Sky High Studios, where your raisin band mates are located.