Nice one.
Your Balloon attempt gave a me a hearty chuckle, thank you, honestly. I have never seen anyone try to go into the starting balloon haha. You need to climb on top of it from the back side :)
Also good job on trying to bind sprinting on ctrl, I am sure you'll get used to it and do much better. Now try using shift after tricky jumps to not immediately fall of a block (like in cactus).
For cactus parkour; you should try jumping on a cactus block and getting the hang of how the damaging ticks work. Try jumping between 2 damaging ticks not immediately after touching it.
E.g.: You jump on a cactus, it hits you once, hits you twice and before the third hit you jump away. Takes some practice, but it's the safest and easiest way to learn it :) Later you can try jumping after the first hit or even bunny jumping.
