I think the latest levels are harder than the previous ones.
I completely agree with you Yosca! I'm currently on World 72's Perfect Picnic, Level 5370 and, even though I am a little behind you, I have had to work extra hard and for almost a week to pass almost every level after #5315.
@frenioz00 Sometimes I run through the levels and then again stuck for days. I can hardly save boosters. I wish I had a lot of hammers and ufos. I usually have to use them all