Just looks like your sample rate took a massive hit. Typically you turn the timebase down to see what you want, then use segmented mode to get many different captures. You don't, especially on a scope with so little memory, want to pull the timebase out and run in segmented mode. So you'd want to do 20us and then segmented for potentially best results. Then you should get multiple high detail captures as opposed to your low detail long timebase + zoom. That'll get you the most bang for buck out of the memory you have.
Final edit: 20ms and zoom does not look good.