My main task will be guide you through a not-harsh-at-all process so you can enhance your experience on this game. If i know Rockstar from something is from that tending to let their old games die, at least here on Steam you will definitely need patches on almost EVERY game from this saga in order to enjoy them properly. In this case, we only need to download one patch, the rest is a minor tweak on your pc.
Note: This patch was tested on 9.3 version of the game. The freeware version from Rockstar Classics it's the same one in Steam.
Thanks to ThirteenAG for the patch, darkyoda21k and SnakeUnleashed. I stumbled with their help on gtaforum while i was looking for a guide for this game, most of this guide is compiled with their answers.

So, let's start with the easiest fix.

Get the patch here: https://thirteenag.github.io/wfp#gta2
Once you got it, paste the files in your game's root folder. It's that simple!
You can zoom in or out by using Num+ and Num-.

Important: No need to adjust resolution in widescreen fix cfg file, if you want the patch to automatically run the game at your desktop resolution.
Bonus Tip: To get windowed mode, simply use a lower resolution in wndmode.ini than your desktop one.

On a side note, you can quicksave anywhere by pressing F5, saving money and speeding your way through the districts!

First things first.. Do not play this game at 60 FPS.. if you must play it at a higher FPS, 35 is the sweet spot or max 40 (this is on foot~ fps goes down when accelerating) is ideal.
60FPS only increases game speed to 2x and that's not what you want. Some games are designed (unintentionally) to just speed up at 60FPS and in contrast, some are (again, intentionally) designed to take advantage of the 60FPS. (Silent Hill 1 on PS1 60FPS is a great example of taking advantage of modern systems).

GTA2 belongs to the latter, its not designed to take advantage of modern systems, and that's not necessarily a bad thing, as the gameplay is already fast, and we don't want it to hit more than 35 or 39 ideally (still better than the game's own 30FPS default. Trust me, 35 - 39 or around that.. that's the sweet spot.

Aight, this one's not hard at all, just read carefully and stick with me. if you find problems try to read every step again.

Optional) Some players may find severe game perfomance issues with the widescreen fix. To remedy this, right click for properties of both gta2manager.exe and gta2.exe and set to "reduced color mode" 16 bit and also check "run as administrator" for both.

1. Turn off frame limiter in gta2 manager as its limiting us to around 25FPS. Our aim is to get around 35FPS.
   
   (Our desktop monitor resolution will affect frame rate so adjust it accordingly to get desired frame rate, ideally 1600x900 for 35plus or 1920x1080 for 30fps)
   
   
2. Press Windows + R and search for "regedit", a windows should pop up. Again, search for "Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\DMA Design Ltd\GTA2\Screen".
   Here adjust "max_frame_rate" to your desired fps, i'll stick with 39 and "min_frame_rate" to 1 (Tip: if you want to lock to 30FPS, then keep max_frame_rate to 1, but for now lets keep it simple and go with 39, as you can change this later.)