I'm just trying to remember what I watched.  I'm currently at work so I can't view the game right now.

In my honest opinion, sentry-immortal all in is difficult to beat.  Sen was lucky to have "beaten" it in game 1.  Parting's immortal/warpprism micro was godly on all 3 games.

Game 1, I remember Sen having +1 melee and +1 carapace.  He had a few roaches (no more than 9, I believe), and flooded with speedlings.  The cost? Sen lost most (if not all) his drones on his 3rd base, a queen, most of his roaches, and larvae that could have been used for drones.  Did Sen really "beat" the all-in?  In my honest opinion, nope, simply because he was behind, not hopelessly behind, but still behind compared to Parting.

Game 2, Sen got his +1 melee and +1 carapace a bit later, and Parting threw down better force fields.  No way Sen could have won that.

Game 3.  This is the clincher.  This, in my opinion, is why sentry-immortal is difficult (if not impossible) to beat at the highest level of play.  Sen was able to scout the Robo.  Parting's sentry-immortal force left his base at 10 minutes (compared to the 2 previous games, he pushed out between 8:30 and 9 minutes).  Sen had at least 1 more minute to bolster his forces, make more roaches, speedlings and spines.  Sen had +1 melee and +1 carapace in time.  Still, Sen lost, even though he knew as early as the 6- or 7-minute mark what was coming.

Having played nDLSoap last night (he's a diamond Protoss), even Soap would have executed a fairly powerful sentry-immortal all in.  Soap had very good mechanics, going +3/+2 in no time against me.  So taking that into account, even at the platinum/diamond level, the sentry-immortal all in is darn unbeatable. 

A suggestion I've read is to attack the sentry-immortal deathball on 3 angles.  That won't work.  Any platinum protoss could throw down decent force fields.  Maps are of no help: the narrow entrances to the 3rd of Daybreak and Ohana just wont allow the Zerg to attack from 3 angles.  The 3rd on Cloud Kingdom may have 3 directions for attack, but Parting went through the side, thereby allowing only 2 points for attack.  And Parting is Parting after all, he can throw down force fields with his eyes closed.

Even Day9 wanted Sen to beat the sentry-immortal all in.  That would have been the best Day9 Daily ever: How to beat the sentry-immortal all-in.  But alas, Sen lost 3 consecutive times to it.

As I watched them replays, it was basically game over for Sen at the 9 minute mark for all his games against Parting.

So how do you beat sentry-immortal?  The only answer I could think of is Zerg returning to 2-base play.  There is just no way for a greedy Zerg to have a decent army by the 9th minute or before lair tech hits.

Any diamond and up Zergs willing to comment?

As strong as the all-in is, it is not usable in loads of maps. If you scout it, you can overcome it.

This doesn't really help a lot, does it?

Please explain how Sen lost in game 3 when he (Sen) already knew what and when it was coming.  Like I mentioned in my post, Sen had a full minute to bolster his defenses because Parting came out at 9:30 minutes and arrived 45 seconds later at Sen's 3rd. 

Please expound further as I want this build countered to bits.  Which maps in the current ladder pool can you not use this strategy?  How do you beat 10 sentries worth of force fields with roaches and speedlings?  Where and how do you engage, when the force fields limit the zerg's attack options?