As I get closer and closer to the end of the feature development for my game and the beginning of the graphical overhaul, I keep thinking of ideas for graphical effects that would make my game even better, but Slick2D is so limited in terms of graphical capabilities. The LWJGL layer is exposed, and thus, basic OpenGL functions, but I don't know anything about the various blending functions and other functions available to me.
A couple of the most basic things I need to be able to do are to be able to properly blend images and primitive shapes together, and to be able to create a proper lighting system. As of right now, I simply have a black and white "stencil" for my flashlight that I blend with a flat black layer that's drawn over everything and set its opacity so it sort of looks like a flashlight. However, I'd like it to look better and to be able to have other light sources in the scene.
Also, I'd really like to be able to have "glow" effects, such as electricity or fire that brighten up the scene and don't just look like flat pixels. Is it as simple as additively drawing these images/shapes to the scene? Or is there more to it?
I know Slick2D is horribly outdated and no longer supported and I never should have used it, but it's definitely the last time I'll be using it. I only went to it because Java has limited game libraries available and LibGDX was giving me a lot of trouble getting started.
I'd appreciate any articles and examples.
EDIT: As an example of the "glow" effect, here's a neat explosion effect created in Unity that I found on /r/gamedev. It would be great if I could get something like this in my game.