The first thing you'll notice playing this game are the awesome graphics. The graphics engine developed for Ace Combat 4 is definitely one of the most impressive seen so far on any gaming console. The game runs always at 60fps, rendering at the same time a high number of planes and enormous environments with no pop-up or aliasing issues.
The planes are absolutely identical to their real counterparts, built with an extraordinary number of polygons, smoothly animated in their mechanical parts, boasting reflections and shadow effects that look just real.
The environments are gorgeous too. Water and weather effects, millions of colors and great textures create a continuous spectacle made of sea, mountains, glaciers, canyons, a show of such a beauty that really impressed me.
Anyhow, just like it happens in great part of flight simulators, when you approach the ground the terrain reveals its blocky nature, and becomes evident that Ace Combat 4 is a videogame, and not a movie. Also, explosions are not even close to what was shown in LucasArts' Starwars: Starfighter, where you could see the ships actually exploding in the air. In Ace Combat 4 you see the fire and then the plane disappears.
Anyhow, Ace Combat 4 remains one of the best looking games ever seen on any platform. A must see, really.