Thanks for giving such elaborate feedback! I agree that the tutorial is lacking, if I didn't have a time limit I would have probably made some kind of visual to demonstrate the mechanics like a bot or something. It was hard to estimate the difficulty level because both of the people working on the game are pretty familiar with this style of movement and we procrastinated any and all content to the last day so I was kind of delirious after making maps for 7 hours straight. The intent was for the player to utilize rocket jumping even in the previous levels to shave off some time and I tried to communicate that with the placement of pickups but that again is a lot easier to register when you have already internalized that piece of movement tech.
As for the softlock you got, could you please explain what was keeping you from progressing? I recall a level loading bug on that map but don't think it could actually limit your progression in any way so I'm curios as to what happened on your playthrough. You didn't miss any gameplay though, that was the last room before the outro map.