Okay, I haven't experienced it on the computers I played it. I will try on my older laptop. Do you experience this effect on any machines?
I've just uploaded the latest version (as per the exchanges with Boopy2), which includes health restoration at the beginning of each level.
I am not sure about restoration at each checkpoints, but if not, it's probably then sensible to add in the main menu a load level option to restart the current level. I will play a bit with it and experiment to see what can be done.
And thanks again for giving me feedbacks :D
I've tried it on my home PC again and it seems that you may be using a few synchronization calls too many per frame.
You may shave of some cycles if you wrap the sync-call routine into a function that checks if it has been called before in the current frame and only updates the sync variables during the first call.