Continuity mistake: During 'Work It Out', when Troy is finished tapping on the gold cookie tray Gabriella places it on the bottom shelf of the large prep cart. That tray repeatedly goes from right-side up to upside-down in the following shots. (00:23:15)
Continuity mistake: During "Work This Out" after Troy and Gabriella put away their spoons in buckets, the next shot Troy has a set in his right hand which he places on the table. (00:23:30)
Continuity mistake: During 'Work It Out', a dark brown pepper mill is lying under the large prep cart which disappears and then reappears. (00:23:30)
Continuity mistake: At the end of "Work This Out" the group take to the center of the kitchen floor for the final dance routine. To the left, the long white apron string either hangs down or lies on the table over and over again. (00:23:55)
Continuity mistake: The binoculars in Ryan's right hand disappears and reappears after the sprinklers have been turned on, when he and Sharpay spy on Gabriella and Troy. (00:27:15)
Continuity mistake: When Mr. Evans shows up in the helicopter, its blades are still spinning at a fast clip when he exits in the close-up. Problem is, the blades are not creating the distinct whirling shadow (nor is there any wind caused by the blades) on the surface of the red chopper, that we see in the two wideshots. (00:34:10)
Continuity mistake: After exiting the helicopter, when Mr. Evans is walking towards his family in the shot facing him, his golf club is in his left hand and swung over his left shoulder. Next close-up from behind, his club is in his right hand and over his right shoulder. (00:34:25)
Continuity mistake: Both Jason and Chad, who are wearing blue shirts and white aprons, are serving burgers, when Troy tells Chad that he wants Swiss cheese on his burger. Next shot in the kitchen, when Chad hands that burger to Zeke to add the Swiss, behind him Jason has been on kitchen dish duty wearing the green tee and blue apron. He can't be in two places at once. (00:57:55)
Continuity mistake: At the piano, Kelsi clutches the sheet music titled "Troy and Gabriella's Song" facing out, but when Sharpay grabs it, in her close-up the title is not written on either side. (00:58:35)
Continuity mistake: At the U of A basketball court, in the overhead shot Troy sits down beside a crumpled white towel, which disappears in his close-up as he calls Gabriella's cell. That towel returns in the subsequent overhead shot, when he continues to play basketball. (01:08:40)
Continuity mistake: During Sharpay's version of "You Are the Music In Me" after she tosses her red jacket atop the piano it moves from front to side, again and again, during the song. (01:12:25)
Continuity mistake: Before "Gotta Go My Own Way" in the kitchen scene, the bracelet on Gabriella's wrist is on her right wrist, but when she goes out to confront Sharpay, her bracelet is now on her left wrist. It stays on her left wrist until she gets to the lockers, then her bracelet is back on the right wrist and stays that way throughout the rest of the song. (01:13:50 - 01:19:55)
Continuity mistake: After winning the Star Dazzle award, Ryan hugs Sharpay with the trophy in his hand. Part of the star at the top breaks off (watch Kelsi's face as it flies past her), as the rest of the star on the trophy bends down. In the next shot the star is intact. (01:43:05)
Revealing mistake: After Ryan is given the Star Trophy at the talent show, the classmates gather outside holding lanterns. The line pulling Troy's lantern up is visible, just as the first blue fireworks starburst explodes above it. (01:44:10)
Continuity mistake: During "All For One" at the pool party, mid-song the six singers split up into two groups of three - two girls and a boy and two boys and a girl; Sharpay, Troy and Chad walking down to their right (viewer's left) and Ryan, Gabriella and Taylor walking down to their left (viewer's right). Next shot, still singing and walking down, the three girls are walking to their left and the three boys are walking to their right. (01:46:20)
Revealing mistake: When Troy crouches down on the rocks, and leans down to see his reflection in the water, oddly the reflection is not reversed, yet his hair is combed the opposite way. (Did the director actually think that if Troy's hair was combed the opposite way it would pass as a reversed reflection?) Additionally, when he crouches down, the bottom button on Troy's shirt is unbuttoned, but in the reflection (as well as in the previous and following shots) the bottom button is buttoned up.
Continuity mistake: During "Work This Out" in the close-up when Troy sings, "A way to have fun," his name tag disappears, then reappears.
Continuity mistake: At the start, when the camera pans through the doorway, as Ms. Darbus speaks on the 'stage', there is nothing between Zeke and the doorway. In the next shot, a tall wood stool appears out of nowhere right beside Zeke. Also, the height and structure of the stool he is sitting on changes.
Audio problem: When Troy and Gabriella are singing "Everyday," Troy sings with his microphone away from his mouth numerous times during the scene, yet he is still heard just as well, and not at a lower level, like he should be. (Within the context of the film, this is sung live on stage and is not implied to be pre-recorded.)
Visible crew/equipment: Throughout the film, set equipment such as the boom mic and pole, reflector screen or monitor are visible in the reflections of characters' eyeglasses and sunglasses. Such as when one of the Sharpettes asks, "So what's the theme of the summer's talent show?" in Sharpay's next close-up the boom mic and pole are visible in the reflection of her sunglasses.
Answer: It's a Musical. Instruments that aren't shown are always playing like this in these types of movies.