Thanks.
I can't yet see what the problem with 2-3 might be, but I can somewhat understand with 1-4. Looking back I think the level design in 1-4 kind of encourages the mind to forget that the levels moving (I might not be explaining clearly but yeah). Anyhow I'm very sure that there's no discrepancies like bugs or physics differences between levels.
Honestly there's no good reason why water was the last mechanic. It was basically because I created a few new levels after I created a new mechanic and it just happened that I made glass > lava > water. It was the type of jam game where I made the base game and then just added mechanics and new levels until I ran out of time. But these are EXCUSES, EXCUSES (lol)... I didn't think about it but I probably should've.