Carbonation Testing & Cold Conditioning

Today marks day 28 of my Mr. Beer homebrew expirement.  Following the 2-2-2 pattern (fermentation, warm condition, cold condition), that makes today the first day of cold conditioning.  I put half of my 1 liter bottles in the fridge, and left the other half in the pantry for extended warm conditioning.
 

I also put the trub bottle I collected during bottling in the fridge so I could test the level of carbonation.  Once the trub bottle got cold, I cracked it open.  Here's a video.

As you can tell, it is is carbonated, but it doesn't hold a head together very well.  Also, the bubble streams continued for at least 15 minutes  (might have gone longer, but I drank it by then!).   The best comparison of the carbonation is that it's bubbly like champagne.  You can see the little streams of bubbles on the photo below.

I posted a question on the Mr. Beer Fans community web site to determine if this is normal for this stage or if there is something wrong with the batch.  The pros told me that 6 hours was by no means long enough, and that I lost most of my carbonation when I opened the bottle.  Cold conditioning for at least 48 hours allows the CO2 to absorb into the beer, and I just didn't give it enough time.

Bubbles aside, the beer tastes like... beer!  Slightly sweet, light bodied, and totally drinkable.  I am curious what it will taste like once it has fully conditioned, and also when the extended warm conditioning is complete for the remaining bottles.