this is one of my favourites to play, or possibly the best, but unfortunately i can't say much about the platforms you've made as I couldn't get past one part due to the large platform not respawning or lifting me up properly like the first time i played and me dying a lot - my fault sorry lol. The infinite lives and autosave helped a lot here and i hope others get further and see more than myself because Im sure there are plenty more good stuff to see.
every platform i have seen was placed perfectly, I did get to enjoy being lifted whilst dodging the spikes the one time which was really fun, some other platforms I really like are the seesaw and the steps which you create by jumping on them. The lift down was a brilliant platform with great potential, especially as you can only use it once, you could maybe have some things to collect on the way down to make it more fun.
Everything felt really good e.g. the gravity, controls, sizes / lengths. You should be really proud of what you have made. In my opinion it could benefit with more theming