I only got this brave man soloing the boss from about 12% HP – but he did do it all the way from about 25%. Mad props. He came close (0.x%) but no cake.
We had been in the dungeon for ~7 hours at this point (figuring it all out the hard way – 5 of those hours were probably spent at Slick and Sparki). A PUG (Real Menace) started along with me and my guildie and was also one of the patient ones. Overall the dungeon gave me a lot of faith in the GW2 community and was a great experience. Still have to finish it as we all had commitments tomorrow, er, today. Which means there is a problem here ANet.
The corpse video: http://youtu.be/1u8raTKPoL4
Slick and Sparki
Slick moves away from damage.
Strategy that came close: Have a warrior with a PPT+V/balanced greatsword warrior build face tank Slick into a wall, during pheremone abandon the fight to clean. The rest of the group should match the damage on Sparki, moving away from him to remove puddles as required. Keep Sparki away from Slick.
Better strategy: Have the entire team push Slick into the wall and simply DPS him to hell. Bring lots of condition removal for the fight with Sparki. Balanced builds should be able to complete the fight at melee range to Sparki with enough condition removal. Keep Sparki away from Slick.
Most of all: VOIP helps here. This bit is a hindrance to PUGs.
Clockwork Heart
Likely going to be straightforward once everyone becomes familiar with the tels. The most important thing here, I would say, is survival. You don’t need to be the quickest or most efficient party in EU/NA – continuous resets caused by rushing will take more time than just taking it easy in the first place. You have 30s or so after he gets his 30 stacks of the shield to start reducing it (before he smacks you all to the ground), plenty of time to position him perfectly. If you keep dying use your opportunity while you sit on the ground to learn his tels as your teammates fight him – failure is part of success.