I never owned an Atari, and Frogger was never released on NES. I have a 48-in-1 and I am wondering what the "grenade" icons represent above the timer on the Arcade version.
Duh! YOu can throw the grenades to blow up the cars and truck on the bottom half of the screen. If you hit 2 or more cars/trucks with one grenade you get double bonus points. I think in level 2 you can upgrade the grenades for a rocket launcher/bazooka.
Either that or those so called grenades might represent the number of levels you've passed.
Actually, now it kinda has been released on the NES. A buddy of mine coded a Frogger game for the NES and released it publicly in the last year. You can buy it here: