I think is quite okay, in Singpaore we are more custom to around 10mins of fireworks because the firework is not consider the "main event". The HK CNY new year firework is a sequence of different themes, so 23:23 of 8 themes is length feel just nice. Not only 22:00 is nice, they also consists of rabbit head, coconut trees, 2011, I love HK inside also...
The firework at time 23:23 is interesting. The sparks (dunno what's the proper term) swirls around in different directions. Don't think I've seen this before.
One question, for most of the panoramic views which show the four groups of fireworks, when the fireworks explodes and form some pattern, then I see flashes of light in the sky. What is this? The flashes do not appear like explosions of other fireworks in the background as I cannot see any sparks coming out from behind.