Hi Var. Thank you very much.
The splashes are 2d exports. In the case of the ork thingy, I image-googled 'mountain horizon' or something like that for something suitable then pasted my graphic on top. Then I used the spray paint tool and then the soften tool to blend both together. The warp gate was similar but with a different type of background. The electricity effects were done with two tones of spray paint and a final brush of pure white.
I haven't checked them in-game, I must admit. I hope they don't lose too much quality.