Rocket Launchers is the most powerful weapon. Many kinds of enemies are instantly died and bosses cannot stand long time. There are two launchers in RE2.
1. Anti-tank Rocket
In Leon's story, he get from somebody while he fighting against Super Tyrant. This is the ultimate weapon; Super Tyrant must be died by only Anti-tank Rocket and ATM-4. It has 4 rockets. This rocket launcher also has reloading but you can only see at Ghost Survivor with infinite ammo.
In Extra Modes, Flan - Tofu Survivor - and Daniel Cortini - Ghost Survivor - use it. Flan has full charges and usually uses breakthrough enemy groups. Daniel Cortini has 3 rockets and uses on emergency threat.
2. ATM-4
When you complete Leon's any story in "Hardcore" difficulty with over S rank, you'll get as reward.
This launcher has one charge but infinite ammo. Particulary, no reloading is needed. The damage is powerful as Anti-tank Rocket's. Most of enemy units is completely died even they're swallowed up the blast. Ivies are died too but only direct hit. Tyrant - not Super Tyrant - isn't died but will be neutralized; all of weapons are too.