JohnnySix: That baffles me, I have no idea why would the spritefont flash whenever an unrelated object with additive effect would spawn. I don't know how to recreate this, either.
Guess I'll dig into the source code and attempt to work effects in. Also, thanks for the icon, it'll be used for the next release! :)
simwhi: I want to keep the spritefont simple, loading by individual tiles would have introduced several drawbacks and complicate the already messy source :P I've used non-equally spaced fonts as well, basically I placed them manually in an image editor with grid enabled. A lot of work if your font contains a lot of glyphs, but only needs to be done once.
Right, guess it's time to look into those effects...