Adelscott's late gas expand build is really outdated and not at all recommended.
I practically go 3 gate robo into colossus every game. Basically if they hit a 7min blink stalker push you need 1 immortal, 8 minutes you need 2 immortals. Counter fast expansions with 2 colossus timing push w/o range. There are subtleties in any PvP build where you can eek out advantages everywhere from beginning to end, you basically just need to have a plan going in to a game to learn from what works and doesn't work and go from there.
Just saw the gate robo gate gate suggestions, this build dies to really aggressive 4gates and can't be disguised well enough to not die to regular 4gates.
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