I’m re-doing a couple of particle effects that I wasn’t entirely happy with using the built in GameMaker Particle System effects.
This has been pretty easy so far, i’m using a tool called Sparks that Nocturne over at the GM forums has created and been kind enough to share.
It allows you to play around with graphical effects and tweak them on the fly.
There is also a good write up over on the yoyogames wikki Beginners Guide to Particles
Here are a couple of previews: