(at around 35 mins) When Jane is preparing syringes to shoot up Jesse and herself, she holds one syringe in her teeth while she prepares the other and it changes orientation between shots.
After Jesse tells Walt that Combo is dead, Jesse has a brief conversation with Skinny Pete about Combo. Skinny Pete says that Combo called him before he died saying that 'a couple of dudes were mad-dogging him trying to run him up off the corner'. However all Combo told Skinny on the phone was that he's 'up on 2nd and Hazeltine, getting eyeballed hard'. This isn't a continuity error, especially given Skinny Pete's propensity for inaccuracy and exaggeration when explaining things. Even at the base level, the two descriptions can mean the same thing to different people.
When the kid shoots Combo, the bullet passes through Combo's drink, then into him. But Combo is holding his drink up in front of his chest and the bullet hits him in his belly. This shot is further impossible as the kid is smaller than Combo and has to shoot up at Combo. This is the true "magic bullet" as it is fired up from the kid, goes through the drink in Combo's hand, then down to Combo's belly.