@10:35 when you scan, you see burrowed roaches. They tunnel, and then pop up in the middle of your army. Works well for Zerg as the greatest weakness of the roach is limited range/speed. In a big fight head on, many roaches can be stuck trying to make it into their range.

So when you scan those Roaches burrowed (easiest to tell by the Zerglings, imo). You want Detection. Turrets or Scans or Raven. While the unit is burrowed, it is defenseless (free kills), so if you have a scan and he catches you off guard. Throw it down as he tries to retreat. A Raven can travel with your main army and provide continuous protection. Turrets are good at anywhere you want to defend (mineral lines, chokes/walloff).

@11:50 You snipe his 3rd, and have a lot of exchange of units. Then immediately push up ramp to natural. At this point you are on 3 base, he is on 2. With both your mains mining out. You have an economic advantage.

The way you pushed up the ramp hurt you. Medivacs were not close enough to MM ball, so they could only heal a fraction of your army. Tank was not in siege mode. Liberation Zones weren't there. Basically, the ramp is good, but you didn't force him into a prolonged battle head on. He was able to stutter step his roaches around you and maximize his damage output.

2k in the bank after you snipe that base, so maybe next time convert those into army/production/expo, regroup, then resume the attack?

With Ravagers, try to keep an eye out in the fight for the glowing orange indicators on the tiles (ground). That is the Corrosive Bile and it will destroy important things quick. Keep dodging it and fighting inbetween rounds of CB blasts. If he has little/no roaches, it doesn't take too many stimmed marines w Medivacs to shred some Ravagers by stutter stepping into them.

TL;DR: I think the mobility and surprise of burrowed roaches got you. Next time you spot burrow slap a Tech Lab on the Starport (or float to adjacent Tech Lab) and make a Raven or two. Then watch his Roaches tunnel to their death.