1. You only need two forcefields to hold waves from the north (bottom of ramp). You technically need two FF for waves that come from the south (the choke point before the ramps), but you can get away with 1 for the very first wave (kill all the zealots before they get through) and 1 for the tank wave (too big to get through that hole). You only need one for the one wave that comes through the rocks once they go down (that roach/hydra wave).
2. Switch HT after every single storm, sentries I switched after every 2 FF or 1 hallucination. Sentry micro wasn't so important, since FF is so cheap. I didn't have any problems with sentry energy.
3. The protoss waves that come from the S are the most annoying in the whole challenge, you'll need 2 storms at least, 3 minimum when the immortals come.
4. Don't feedback the ghosts. You need to storm the marauders or hydras (depending on the wave) anyway, ghosts die to the storm before the marauders do, it's just a waste of energy.
5. Split your sentries up on both sides of the destructible rocks for the ultralisk--he'll dance around not knowing which side to stand on before attacking the rocks, giving you ample time to DPS. One storm is enough. Rocks should be at yellow or early red when he dies.
6. Dance with the roaches behind the rocks, sentries outrange them. Don't dance with the hydras. You will lose. Bring them down into a clump with a first storm; then when the rocks go down, FF quickly and then storm a couple more times.
7. The viking + MM wave is also pretty annoying. You need two hallucinated archons to take their fire while you storm--probably at least 3 times. Pull back instead of FF and sitting on the high ground, since they'll have vision from the vikings, choke/FF/high ground useless.
8. Battlecruiser gets 3 hallucinated archons tanking, one feedback, one storm, sentries DPSing
9. Mutas also get hallucinated archons tanking while storm/sentries DPS. I imagine guardian shield would be good here, but I didn't bother.
10. The wave with just 2 tanks you need 1 forcefield and nothing else, sentries kill it from the high ground before the next wave.
11. Last ultralisk wave my sentries all died, so I stormed twice and then morphed into archons. Turns out 3 archons (with micro) beats 1 ultralisk, then 1 thor, then 1 mothership (after a bit of kiting to frantically regen some shields). I might do this again just to feedback that motherflipping mothership.
12. Finally, note that the better you do in earlier rounds, the easier you have it later rounds--more units alive = more energy regen/second = more storms before you have to morph into archons.