The significance of “Wrong Number” in Hotline Miami 2

So far I've found 1 alternate ending:

Jake:

On Jake's last mission, Withdrawl, if you clear both floors without dying, you'll be treated to an additional cutscene involving 50B. In this cutscene Jake goes along with the leader of 50 blessings to a safe house, only to be killed by him. Canonically, he is incapacitated in the final mission of his, then dragged to another room and shot in the head (leading to you finding his mask in Hotline Miami 1)

Evan:

• On the 13th scene, Subway, in the intro, if you listen to the answering machine before leaving for the subway, you will be able to experience an interesting cutscene after completing the level.

Here's some of the gameplay differences I've noticed:

You can take an enemy as a human shield in HM1, but not in HM2.

In HM1, if unnoticed, you could run up to an enemy and immediately execute him (Space in PC) without needing to knock him out first. This can not be done in HM2.

The tiger mask (Tony) in HM1 can pick up and use guns, while the tiger mask and similar melee-only masks or modes in HM2, can not.

There are longer sightlines in HM2 compared to HM1, enemies might be able to shoot you even if you can't see them.