Okay, I tried what you said and got a 0:19, but I don't think that's the reason why. I'm sure you're aware of this, but if you're not I found a way to jump over the wall after the "speed bumps" leading to the escalating stairs near the end of the level. I haven't seen the speedrun of this level, so I don't know if this is used or not. Have a look:
http://www.geocities.com/eonouzo/StarLightZone2in19.zip
The time can easily be brought down to 0:18, possibly even 0:17. The jump before the crumbling floor at the beginning can be done better. This is merely a demostrational video.
EDIT: Okay, just brought it down to
0:18 barely.
EDIT2: Woohoo!
0:17 reached! BTW, I had to slowdown at the end because of the formation of the rotating platforms.
P.S. I realize Star Light Zone is a long way from where you're at, I just hope I can motivate you to continue on :)