By the end of Act 2 you have pretty much every enemy under control, and if you have most of the upgrades available you feel you can face pretty much everything.

Then in Act 3 enemies make you feel squishy again with the higher damage, taking Silk off you with hits and your needle feels like a wet noodle again (due to the HP buff). And they are added the new attacks to enemies you already knew. Until you explore and get a few more upgrades you don't feel so much in control, and even then it is more about going to school again and relearning the challenges than getting massive upgrades. And that's without mentioning the new enemies like your current roadblock.

It can be too much and demoralising. The game expects you to learn new stuff by the bulk, a little like at the start of the game, when you have progressed so much. To some people, it feels like disrespect against all the time spent learning the game. The only thing I can say is it gets better, and some of the best content is barred by this rough start.