i got some sentences I can't understand!
1. Not letting that stand!
This is a voice line from 'Overwatch', which is a video game. One of the characters say this sentence when she respawns. What does that mean and when i can use this sentence?

2. Have some of that!
I forgot where I got this sentence :( What does that mean?

3.Let's see them aliens.
This sentence is from a news when they are saying something about "Area 51 raid".
I guess it means that "Let's see whether they are aliens or not" Am I correct?

4. Thank you so much for packing my shopping for me.
This is a line from a movie "deadpool". I guess that means "Thank you so much for packing my stuffs that I've just bought" Am I correct?

I need your help native speakers and I always appreciate it ·ᴗ·

Question

i got some sentences I can't understand!
1.﻿ Not letting that stand!
This is a voice line from 'Overwatch', which is a  video game. One of the characters say this sentence when she respawns. What does that mean and when i can use this sentence?

2. ﻿Have some of that!
I forgot where I got this sentence :( What does that mean?

3.Let's see them aliens.
This sentence is from a news when they are saying something about "Area 51 raid".
I guess it means that "Let's see whether they are aliens or not" Am I correct?

4. ﻿Thank you so much for packing my shopping for me.
This is a line from a movie "deadpool". I guess that means "Thank you so much for packing my stuffs that I've just bought" Am I correct?

I need your help native speakers and I always appreciate it ·ᴗ·

Answer

1.  To “not let something stand” means to fight back against an unacceptable situation and try to change it.  Example:  “The government has just passed a law that takes away our liberties.  We can’t let that stand.” 
2.  “Have some of that” (or “take some of that”) is something a person can say after attacking an opponent.  “That” is the attack, damage, or abuse that your opponent is being made to suffer.  It can also be used in non-physical contexts, like a chess game: You put your opponent’s king in check, and say “take some of that.”  
3.  It depends on context.  The speaker may believe there are aliens and is simply saying he/she is eager to see them, or he/she may doubt there are aliens and wants to see whether or not they are really there. 
4.  Yes.