Hotline Miami

You can find most of those weapons on enemies or unlockables by grinding points.

I used the chapter 4 Tension as it has a spawnable location right at the start (west room with two guys) and that was how I farmed the unlockables.

But there are a few special melee weapons that need to be grabbed and used in certain chapters.

The Briefcase in the Prelude chapter.

The Pot has two variants: Full Pot on Ch2 but the ones that counts is an empty version on Ch4.

The Crowbar can only be found in Chapter 5, its in the first carpeted room.

The Frying Pan is in the second floor of Ch5 and in the 3rd floor f Ch7, both times on a stove.

The Drill can only be used while wearing the Carl Mask, the mask can be found on the body in the first floor dancing room during Ch8.

The Baton can only be obtained from police during Ch 13.

Finally, some chapters have Pool cues on Pool tables, you need to kill an enemy with a pool cue to instantly get a broken pool cue, use that too.

Useful Link: https://hotlinemiami.fandom.com/wiki/Knife_For_Pros

Necessary weapons:
Knife
Baseball Bat
Lead Pipe
Golf Club
Crowbar
Pool Cue
Pool Cue (broken)
Frying Pan
Pot (empty)
Baton
Katana
Machete
Sledgehammer
Fireaxe

Not sure why the achievement says "brick" when bricks stop at the first enemy they hit. This achievement can be unlocked by throwing a hammer instead.

I got it on chapter 5 on the second floor. You can keep retrying until a hammer spawns from the first enemy (or try to get it from the first floor,) then clear the second room, and then try to line up three enemies in the top right room. Two enemies walk around while one is stationary and they are in a straight line fairly often.

I use the chamaleon mask to clear rooms a little more easily, but you can also use the Jake mask to make the brick lethal.

This one worked for me: (Excerpt from https://hotlinemiami.fandom.com/wiki/Combo_King)

This can be easily gotten in the third floor Chapter 14, Vengeance, as the many enemies near the starting point are situated close together and are either dogs or mobsters with melee weapons. Enter the third floor with a melee weapon and kill the mobster in the room on the left, then the two dogs and mobster in the room on the right, then the two mobsters in the bathroom above, and then return to the room on the left and head upward gradually, killing each of the six mobsters that runs towards you. You should have killed 12 by the time you reach the thug and the mobster with the firearm in the windowed area at the end of the path. The Zack Mask will also be helpful although it is not necessary.

I liked Grinding Chapter 1 instead of Chapter 2, its fast and easy.

Fist them all, Tony!

If you are having trouble, pick a gun to finish the last two.

Here's a video of how I grinded it, takes me like 40 seconds per run.