The games aged rather poorly, especially the older Crash 1 and 2, especially in game difficulty standards. Both had really crazy spikes in which the game became frustratingly challenging. This was somewhat fixed in the third installment, but it also had similar situations. And these games were marketed towards children. Man, the times have changed since then.
The graphics on PS4 are colorful and nice to look at, and so are the refreshed animations, however, the controls have a little bit of a lag to them. Probably something that was ported along with the original Crash's movement, but it was enough to be noticeable, especially when the game tasks the player of doing a pixel-perfect jump. And there are a lot of those.