Corrected entry: During the fight scene in the appartment of "She", Machete appears out of nowhere from behind the guy in the kitchen. There is no way he could have walked over there without all the guys seeing him.
Correction: Machete didn't walk over to the kitchen past the guys, he was hiding in there to ambush them. The reason you (and the guys) couldn't see him was because he was hiding.
Corrected entry: In the hospital when Machete drives through the guys on the metallic bed, there is no person under it and no way someone could hide there. In the next scene Machete suddenly appears next to it as if he would have come from under it.
Correction: In the context of the scene Machete WAS under the gurney. Neither the movie viewer nor the villains could see him but the style of the movie requires suspension of belief in order to show how skilled Machete is at what he does. As the upper underside of the gurney wasn't visible (due to the sheet hanging down) one can presume that Machete was clinging to the underside, not lying on the lower part.
Corrected entry: When Booths Guy show up at the hospital, they ask for a man just brought in (Machete). The girl at the front desk says he needs to go to "his" right while pointing towards "his" left.
Correction: Character mistake at best. She is deliberately giving him wrong directions, and messes up a bit. But since he knows she is lying (as evidenced when the gang starts opening EVERY door in the clinic instead of following her directions), he does not really care or pay attention.
Corrected entry: Shortly after Machete tries to kill the Senator, he got stuck on a roof shooting all the 4 guys of Booth in the knee. A day later these bodyguards are walking around like they have never been shot in the knee. They should all be in hospital for weeks in reality.
Correction: This being a Grindhouse movie, a lot of reality has been ignored including people's injuries. Machete himself takes multiple wounds from bullets and even has his leg chopped up then continues on without so much as a limp. It is all a part of the over-the-top dark comedy feel of Grindhouse movies that this was done.