blaarg's filter only makes those rgb dots which tv's use. Really, the only way to make it look authentic is to play it on an old tv. High contrast just depends on sprites. Color bleeding can be done with a shader.
<img src="http://blargg.fileave.com/ntsc-vs-palette/sms_ntsc.png">
Umm it does *way* more than that. Those artifacts around the edges? this is a PNG. It's not jpeg artifacting, it's NTSC artifacting and it looks *just* like an old TV. It's uncanny.
Note that he has a lib for NES, SNES, Master System and others emulating the exacts artifact that each graphics chip produced.
So yeah, you'd have a "NES-look" effect or something like that. Very specific.
It does look like a lot of work though, bringing it into Construct. I'd be up for it if I knew anything about HLSL.