The demo works perfect with the Xemu emulator:
hm, not quite 100% perfect...
on the real machine, the sprites are in bitplane mode, i.e., each sprite sets its corresponding colour bit (sprite 0 = bit 0, sprite 1 = bit 1, and so on), so the effect is that the sprites are changing the colour of the colour bars in the background.
I have tested your sprite demo on the Nexys board. Here it works as you described:
Bitte melde dich an, um diesen Anhang zu sehen.
Bitte melde dich an, um diesen Anhang zu sehen.
A curious thing is, that it also works with line 90-110 being deleted (without init VIC-IV and no pokes).
Bitte melde dich an, um diesen Anhang zu sehen.
It seems that these lines aren't needed on the MEGA65 (Nexys board) for showing your sprite effect? 