The grenade launcher is a slightly situational weapon that inflicts a large amount of damage over a larger area, but can be difficult to aim in close quarters and is not suitable for rapid fire. It also has a smaller ammunition capacity than most weapons and the grenades don't travel very far. Grenades are most helpful for clearing out larger hoards and bosses but can also be useful for clearing out enemies in a room before entering it. The launcher can eventually be used to bounce grenades off walls and into enemies around the corner. This weapon is found in a mission that is optional to the main quest line.
On upgrading, the grenade launcher gains a larger explosion radius, increased projectile distance, increased firing speed, and the ability to bounce off walls and latch onto monsters, exploding after a short delay.
I noticed that the larger grenades also fit the barrel. Each charge now spreads 30% more, increasing damage over a larger area.
The new propelling charges really pay for themselves, hurling grenades much farther. The grenades themselves now contain a contact censor that can distinguish between walls and targets, allowing you to hit a target behind a corner.
Just a few replaced parts and the weapon now fires 25% faster.
Can't cram larger grenades into this barrel; these are little nukes! But it gets even better; the grenades now stick to the target and detonate after a short delay! Incredibly devastating to groups of enemy.