Hi MG

DMP or DeathMatchPlus is a Quake 1 Multiplayer Mod which was IMHO a whole lot of fun to play as it added new weapons and powerups rarely seen in quake at the time. I will always be grateful to Zop for trying to help as he very kindly contributed a number of updates a few years ago and the updated prototype is on newyork.quakeone.com:26002. Yes there are a number of bugs but the changes felt well balanced and didn't detract from the look and feel when you played it.

It looks like there is a Wiki page at https://quake.fandom.com/wiki/DeathMatch_PLUS_PACK! but it doesn't quite do it justice. I would certainly be looking to add some/most of the DMP, RuneQuakePlus (RQP, see newyork.quakeone.com:26009) and Rquake (co-op mod at newyork.quakeone.com:26001) features in any FPS if I could manage it, purely for the fun they can provide if you use them wisely ;) .

Hope this helps

Monty

Collision

Continuous will collide with any component that does not have a static mesh geometry attached to it. This will eventually create problems. When you start to create monsters they will obviously have a static mesh geometry and your bullet will not work. Continuous Dynamic will collide with anything but, it comes at a processing cost (maybe a huge one). No matter what you use, projectiles can still potentially go right through something.

Your solution is not wrong. However, you are eventually going to have to consider adding your own approach to what already exists or live with possible missed collision checks and bad frame rates. There are a lot of ways to do collision detection but the easiest for bullet~enemy collision would be to check if the bullet co-ordinates are inside of the enemy co-ordinates. You can do this with either a point or intersecting boxes

pseudo code for point

function isPointInsideAABB(point, box) {
  return (point.x >= box.minX && point.x <= box.maxX) &&
         (point.y >= box.minY && point.y <= box.maxY) &&
         (point.z >= box.minZ && point.z <= box.maxZ);
}

pseudo code for interecting boxes

function intersect(a, b) {
  return (a.minX <= b.maxX && a.maxX >= b.minX) &&
         (a.minY <= b.maxY && a.maxY >= b.minY) &&
         (a.minZ <= b.maxZ && a.maxZ >= b.minZ);
}

By using the continuous option to check non-rigidbody collisions and incorporating your own function for rigid body collisions, based on a switch that can be turned on/off, you can have the best of both worlds cheaper. For instance, you only have to run the intersection codes when something fires a projectile or when an enemy has gotten within a certain range of the player (for player~enemy collisions).

This video gives a decent description of the 3 collision types as-well-as an example of them all in use.

Cloning

You may want to consider using a pool. You said the grenade makes a copy of itself. I'm assuming this means you destroy that grenade once it has done it's job. That is not good. Look at your code as a pregnant lady. Labor is hard. If a woman had to give birth to the same kid every day there would be a lot less people in this world. Your code is no different really. It has to keep cloning the same projectile every time it needs one. This means it has to put a new copy in the buffer and then take that copy out. That is not free. Depending on unity's method that could be expensive. If you knew the max amount of clones you could ever possibly need at one time you could create a pool of clones when the weapon is selected (or even populate the pool as the weapon is fired for the first few shots).

Consider this, you have mathematically figured out that the most amount of grenades that could ever be on the screen at the same time is 3 (as an example). You make a pool of 3 grenades. As each one is fired you mark it in your pool as "inUse". When it explodes, you don't destroy it. You make it invisible, reset all of it's data (ie frame = 0, exploded = false, whatever) and you mark it in your pool as "available". As grenades are fired you simply pull the next available one from the pool. Your current way may entail making and destroying 100 clones. The way I described, you will never make more than 3 and none of them get destroyed until you switch guns.