Flickering sprites

I've made a demo of my game now and it runs smoothly but when I started to create the hud (I use another cam rendering the HUD far away from the ingame scene) all my "static" sprites in the gamescene starts to flicker very much.

The graphics has nothing to do with each other and should not really happen. Have you experienced this? Is it a bug? Rendering issues with several cameras on one screen?

set the cameraRange near value lower... like 0.01

Don't set your CameraRange to 0.01! Sooner or later you'll run into fillrate problems and everything will slow down - not necessarily on your own PC, but it may do on others.

Instead, move your sprites further away from the camera and scale them up if necessary.

Its also likely that you haven't disabled clearing of the colour buffer on your HUDCamera. Check the documentation for CameraClsMode for more information.