Also, here's my feedback so far.
The lucifer cannon fireball looks very nice! My only suggestion (you don't have to follow this) is to make the colors similar. Either make your additions blue, or make the old fireball orange-ish. Maybe you can play with complementary colors. Don't worry too much about particle clipping, as this should be resolved after we add soft particles.
Your pulse rifle shots look nice and I like the red dynamic light. Again, my only suggestion would be with regards to color consistency. Either red or yellow will look good in this case. Or, if you want to make it consistent with the lucifer cannon as both fire plasma, try light blue.
That flamethrower effect is perfect! Seriously nice job!
Smoke particles on the physical weapon shots look very good!
Our mass driver is going to turn into a sniper rifle in the future, so if you make an effect more appropriate for a high-power physical weapon that would be better, but the replacement for the current energy shot looks good.
Nothing was included yet for the las gun, but I'll just remind you that it's going to be turned into a beam rifle soon. If you want us to provide you with the WIP model so that you can test out a beam effect, we can give it to you.
Good work on the grenade explosions. Feel free to make them even flashier, if you want. They are single-use weapons and can afford to be big explosions.
Alien creep looks amazing, it just needs a normal/specular map.
What did I miss? Also, I can't wait to see what you'll do with the dragoon barb. It needs a better explosion than the old one!
Oh, and how did you make all of these? They look great!