Some changes are that the mongoose's body and head are now more streamlined and almost like the real animal. The cobra, on the other hand, now has a smaller hood and head, a more outgoing and friendly personality, and is now a girl character.
They're still pretty much the same characters after all these years, though the cobra's has changed a little. Like I said earlier, she's friendly and outgoing, but she's not as scared of the mongoose as before.
Below is a colored model sheet to show what colors I used to create them. The cobra's now more brown and the mongoose is now more grey, just like the animals they're based on.