indeed on crt you get the faux-transparency effect:

looks nice if you stand in place behind the waterfall - if you start moving then you can notice the cross pattern
maybe it depends on the crt used though as older monitors will surely blend more

The waterfall transparency in the Sonic games only really works if you use composite cables as well, it kinda falls flat if you use RGB 😀.

+1 It even worked best via RF, maybe.
Originally, the MD/Genesis had no composite cables included in its box for that DIN port.

It only shipped with a simple antenna cable, maybe a primitive switchbox made of sheet metal.

Unfortunately, that connection fell out of favor quickly in the mid-90s.
On earlier quality TV sets (analogue) with an AFC (automatic frequency control), the picture stayed stable.

The existence was noticeable if you rotated the VHF/UHF knob and the TV picture started to lock-on automatically once you were near the right channel.
First, the picture was monochrome, then it quickly changed to colour and becoming stable.

https://en.wikipedia.org/wiki/Automatic_frequency_control

Modern TVs that expect a strong, stable signal - like it's usual for cable TV, don't lock so well onto RF modulators.
Because, if the source signal is good, you don't need fancy tuners anymore.
While the modern TVs do have a scanning function, they usually don't re-sync/re-lock in real-time.

Maybe that's worth a footnote in history, maybe.
It's one of the main reasons I think why systems like the Atari VCS causes so much trouble on modern TVs, modern CRT TVs included.
They're not made to expect a weak and drifting RF signal.

In Japan, were SNES and Mega Drive came from, the RF connection (NTSC) was popular for quite long.
The original Famicom had no Composite ports, for example.

Ironically though, Japan adopted RGB video very early on. Most homecomputers over there used it primarily.

Edit: Typos fixed.

it's just a frame-alternating dither and a color cycle. It wouldn't turn into true translucency on a real CRT with a poor dot pitch, but phosphors do that favor partially, and would be just as effective on earlier LCDs. This differs from the Genesis signal-bleed-dependent jailbars (not a CRT effect).

If you want another test of alternating dither fun, see Unreal's (Future Crew 1992) later color blending sequence where this trick is on a tweaked VGA mode beautifully 😀

https://twitter.com/furan/status/156904368787 … 57de9uTYTrbzIow

Here you can see the palette changes on Jack Jazzrabbit. As @leileilol said, just color changes + sprite alternate dithering.

ViTi95 wrote on 2022-09-16, 08:17:

https://twitter.com/furan/status/156904368787 … 57de9uTYTrbzIow

Here you can see the palette changes on Jack Jazzrabbit. As @leileilol said, just color changes + sprite alternate dithering.

The link mentions color-cycling, which was very popular on VGA, also.
Fractal generators used it, too, for example.
One of VGA's biggest strengths was the freely definable palette.

While the mechanism isn't exactly complicated, it's still elegant and moves the hard work to the RAMDAC rather than using the CRTC.

Instead of changing actual pixel data and causing traffic on the bus, merely the color arrangement is changed (pointers stayed, palette changed).

Edit: Before someone complains.. Yes, Deluxe Paint (DP) used color cycling, too. 😀