This is one I had to do from scratch. I used a render of the 3D cat model, then gave it that annoyed expression in Photoshop, along with adding the colors, details, and softening any angles. It didn't take a super long time, tho--I think I did most of it over a weekend. I thought about putting it through some filters to make it look more 16-bit, but wasn't crazy about the effect, and I think it would have been more trouble than it was worth in the end.
Sadly, I couldn't find a font that looked like the one in Ecco's title screen, so I went with one that was really similar to the box art.
The terrifying pre-Photoshop version of the cat can be found here