Introduction
Graphics -- Do not use Windows 10 built in scaling
Graphics -- Adjusting Colors
Reducing Latency
More Appearance -- Scanlines and Reshade
Reducing Input Latency

Turn off Windows Scaling


Windows 10 does not offer proper integer scaling, supposedly. If you do windowed mode non-scaling the game looks as intended but small. I think the game originally ran at 320x224 (a standard was 320x240) for tmnt arcade and turtles in time arcade.



In the Windows 10 control panel under Display

I put windows scaling at 100% so it doesn't scale because windows built-in scaling doesn't work properly.

I also left screen size: original in the options menu of the game. Some video cards, offer integer scaling. With the resolution set at 1024x768 the game looked good at normal and wide screen sizes, but not full. You may have to use programs such as Resolution Switcher or Hotkey Resolution Changer 2.1, if you want to use a lower resolution setting. 640x480 in game resolution may work for some people. It isn't supported by the menu.

I was able to use the Integerscaler program to make the screen boarder outside of the gameplay window black and it hid the window and title screen boarder in the options of the cowabunga main menu. make sure window is not set to full.

Color Saturation, Temperature (hue) and Brightness

As of patch 2 some users have reported problems with Windowed setting in game or the colors of the game being darker. This also may be evident from the trailer screenshots for the games. I think crt monitors or tv had settings such as hue, brightness, and contrast. A setting in Windows to adjust gamma is called gamma helper.
Settings for color brightness or something in AMD video cards are called: Saturation. In Nvidia the setting is called digital brightness. TV's also have a setting called: color temperature. You may want to document settings or create a Windows restore point before changing settings. Newer video driver versions or a clean driver install may help. For AMD cards a user turned off image sharpness.

Reducing Latency or Lag

Notes on video latency:

This game does not offer 4K high definition textures.
A 4K TV, monitor or projector will possibly add more latency than a CRT or 720p TV, due to having to upscale the image to fit the resolution of the tv. I think the game originally ran at 320x224 for TMNT Arcade NTSC. Some game consoles even had lower resolutions. Framerate, hz discussed in reducing input latency, section.

To reduce video latency some TV's and video cards have a game mode setting for this purpose and frame rate improvement.
The original displays were 4:3... some displays offer aspect ratio correction or settings such as panoramic.

Upscaling and DLSS software
Some people use software such as magpie to upscale game images. (0.9.1 is available at this time on github)

Additional Hardware
Some people use mcables, which automatically upscale images when needed.

More options for appearance -- Scanlines, and Reshade

There is software called reshade to emulate the look of crt. You also could document the current values for your display and then change them to your liking. You would then be able to change the settings back if needed. Settings are sometimes available in video card and operating system software. Reshade software has configurations to mimic the look of old monitors. Currently at version 5.4 was able to make my screen look like a pixelated 90s or 80s crt, CRTsim was one of the options. Some people will have to push the home key to bring up the menu, after reshade is installed

input latency:

-- a wired controller can be used.

Framerates are typically set at a max setting. Refresh rate is also another setting

CRT monitors NTSC and PAL had different settings for framerate, hz than monitors types of today.

Limiting frame rate (different than vsync) Helped the ability to do the jump attack. A standard for pal/ntsc was

-- 25/29.97fps.

Controller feedback was also digital and not analog.