Yeah, not being able to skip puzzles is annoying and, honestly, kind of bad design. If I get stalled on a puzzle in SEQ (which for me, started in the Bs), the solution is usually to go solve other puzzles and come back to the one I can't solve. But with SEQ, when I can't solve a puzzle, the solution is to...leave the app and play another game. And then I tend to forget about SEQ altogether.
I'm stuck on D-17 and just finished F-7. I haven't tried F-8 or I-1 yet.
I have been enjoying the game overall, though. It's nice to have a relatively easy game to relax with (especially compared to On-Off, which for me is very difficult). I've dropped SEQ into the folder where I keep my esteemed Pixton puzzles.