: There are a few secrets here. In two places, you will be fighting on areas
: open the sky. Grenade hop over the low walls to get to ammo caches
: including a shotgun and 2x and 3x powerups.
The first area Mark mentions here is the large outdoor pool area. If you stand in the hallway next to the switch by the ledge, it is fairly easy to run out of the hallway and leap onto that ledge. Follow it to the secret area. That will save having to use a grenade.
The other area is in the room containing the Jugg. Before activating the fighters in that room, you can get the Jugg to suicide by letting it fire it's grenades into the large wall in front of it. Since it's vitality is set to 500, that doesn't take long. Then activate the fighters and let the projectile one slap you over the wall to reach the other secret area. That saves another grenade.
Hey, I know it's only two grenades. But as with the Battle Cat, ammo is like gold to me...i'm gonna save as much as I can.