I am definitely getting better at some game types, like the afformentioned Robotron, Defender and Pac-Man. At the same time I am getting worse at other game types, mainly platformers and beat em ups. The platformers and beat em ups are largely memorization games. Memorizing the order of enemies, where they walk, how they attack, etc. I don't have the patience to memorize games like I used to, which is why I haven't really gotten into a lot of newer games like that.
I am especially getting bad at picking up the eccentricities of newer fighting games. I must have like 5 different Neo Geo fighting cartridges and I STILL can't do any special moves in any of them. Although I still have the SF2 and Mortal Kombast special moves for my characters (Chun Li and Scorpion) memorized.