Hey ! I personnaly had some playtests for my game but also for testing level parts I made sure to spawn the player at the highest I achieved each time I made a new part of the level, I was struggling at first by the punishing aspect of falling but now I became good at my game and manages to end to the top one every 2 or 3 tries if I play safely, still I fail a lot when I speedrun but I am starting to get decent times I feel!
I honestly don't entirely remember how I playtested my game to make sure every jump was do-able, the development process is all a blur now. I know I tried to keep the controls relatively easy and made the map layout more forgiving for the player as well as myself. I think I had some ideas for obstacles in mind but generally managed to build the majority of the map from the ground up in just a handful of revisions.
I did drag the player in the editor window to certain parts of the map when I needed to test or practice certain sections but also tried doing a full run through of the game every once in a while. When working on the final jumps and ending to my game I dragged the player up to a position I knew could get to and just went forward from there.
I didn't stress too much on raising the level of difficulty as you climbed higher in my game, I more so just raised the stakes. My ultimate rationale though was that if I could do it then you could too, and I think it worked out pretty well.
