Shayne Lavery, Jordan Rhodes and Karamoko Dembele had given the Seasiders a dominant lead inside the opening 40 minutes, before a brace from Will Goodwin set up a tense end to the fixture at Bloomfield Road.
Critchley states he will take positives from the game, but was disappointed with the way his side performed after the break.
“We made what could’ve been a comfortable night really difficult,” he said.
"We were very good in the first half and played very well- we could’ve had one or two more goals.
"We started the second half quite well and had some chances to finish the game, but we didn’t.
"They changed and that made a difference to them.
"When they get the second goal- it’s game on.
"I was disappointed with our second half, but I have to look at the positives as well and remember we still won the game.
Read more: Jordan Rhodes continues scoring run as Seasiders hold on following late pressure from visitors.
"Maybe we were lacking a little bit of (Ollie) Norburn and Hubby (James Husband) in certain situations.
"When you’re bringing youth on, that little bit of leadership is important in those moments, but that’s where we are.
"The players need to learn, and we will only get better.
"You’ve got to remember we still deservedly won the game.
"They came back into it, and fair play to them, but Grimmy (Dan Grimshaw) had nothing to do really.
"We were the team that deserved to win the game so let’s not forget that.
"I’m shattered because I was getting worked up on the sidelines because you can feel what’s coming or what might happen.
"When we didn’t take the opportunities to go 4-1 up, we’ve all been in football long enough to know the next goal makes the game interesting.
"They got it and that gave them momentum and allowed them to throw men forward.
"Sometimes it’s like all bets are off, but I think we saw it out well in the end.”
Blackpool are back in action on Saturday afternoon, with Peterborough United being the next visitors to Bloomfield Road.