It seems the original version plays just fine. But the newer updated version won't load at all and an error message pops up (see attached). Not sure If it's just the fact that i updated to Yosemite. Any thoughts?

Send a support ticket - http://www.gog.com/support/contact

There was a glitch in the game's launcher preventing it to start on OS X. I don't know if that has been patched meanwhile, but there was a workaround. Right-click the app and select Show package contents.
Inside go to \Contents\MacOS\ and you'll find another HotlineMiami.app. Try to start this one.

Nope, it doesn't work on my iMac. I'm using OS X Yosemite v10.10.2.

Here's what my crash information says when I try to load the updated version on my Mac:

Process: HotlineMiami [1498]
Path: /Applications/Hotline Miami.app/Contents/MacOS/HotlineMiami.app/Contents/MacOS/HotlineMiami
Identifier: com.abstractiongames.HotlineMiami
Version: ???
Code Type: X86 (Native)
Parent Process: ??? [1]
Responsible: HotlineMiami [1498]
User ID: 501

Date/Time: 2015-03-11 17:53:27.237 -0400
OS Version: Mac OS X 10.10.2 (14C1510)
Report Version: 11
Anonymous UUID: ABA7B453-7A68-9F99-FEE3-247C798EF7CA


Time Awake Since Boot: 690 seconds

Crashed Thread: 0

Exception Type: EXC_BREAKPOINT (SIGTRAP)
Exception Codes: 0x0000000000000002, 0x0000000000000000

Application Specific Information:
dyld: launch, loading dependent libraries

Dyld Error Message:
Library not loaded: /usr/X11/lib/libGL.1.dylib
Referenced from: /Applications/Hotline Miami.app/Contents/MacOS/HotlineMiami.app/Contents/MacOS/HotlineMiami
Reason: image not found

Binary Images:
0x8feb4000 - 0x8fee7e03 dyld (353.2.1) <06B1254D-9BB9-327C-BA15-8F18FFF97586> /usr/lib/dyld
0x963f3000 - 0x963f3fff com.apple.Cocoa (6.8 - 21) <6AF80DDB-C28E-36FF-BC11-D7D561AC52A9> /System/Library/Frameworks/Cocoa.framework/Versions/A/Cocoa
0x984bb000 - 0x984caff3 com.apple.opengl (11.1.1 - 11.1.1) <212B409C-AF1E-3C69-B4AA-57A39C35BB62> /System/Library/Frameworks/OpenGL.framework/Versions/A/OpenGL

Model: iMac12,1, BootROM IM121.0047.B1F, 4 processors, Intel Core i5, 2.7 GHz, 4 GB, SMC 1.71f22
Graphics: AMD Radeon HD 6770M, AMD Radeon HD 6770M, PCIe, 512 MB
Memory Module: BANK 0/DIMM0, 2 GB, DDR3, 1333 MHz, 0x02FE, 0x45424A3231554538424655302D444A2D4620
Memory Module: BANK 1/DIMM0, 2 GB, DDR3, 1333 MHz, 0x02FE, 0x45424A3231554538424655302D444A2D4620
AirPort: spairport_wireless_card_type_airport_extreme (0x168C, 0x9A), Atheros 9380: 4.0.74.0-P2P
Bluetooth: Version 4.3.2f6 15235, 3 services, 27 devices, 1 incoming serial ports
Network Service: AirPort, AirPort, en1
Serial ATA Device: ST31000524AS, 1 TB
Serial ATA Device: OPTIARC DVD RW AD-5690H
USB Device: Hub
USB Device: Xbox 360 Wireless Receiver for Windows
USB Device: BRCM2046 Hub
USB Device: Bluetooth USB Host Controller
USB Device: FaceTime HD Camera (Built-in)
USB Device: Hub
USB Device: USB Receiver
USB Device: IR Receiver
USB Device: Internal Memory Card Reader
Thunderbolt Bus: iMac, Apple Inc., 22.1

Is there a file I'm missing somewhere? Has this problem already been fixed and I'm just not finding the proper thread?

Seems like X11 isn't properly found/installed on your system.
Re-install XQuartz, that should solve the issue.
https://support.apple.com/en-us/HT201341

I just found that out a few hours ago. Installed the package and it worked like a charm. Thank you!

You're welcome ;-) Don't know if you ever solved it, as the OP is rather old now, but the X11 issue might apply to you as well.

same problem here ;/ original version play fine but have horrible screen tearing ;/