Beta 3: Citadel of Dr. Cassiopus

[divadnala]

370C1A010C1B630 wrote: About that coin for example, I think you could have gotten it by jumping from a suitable spot on the floor below.

You can get it by jumping from below, but it's also possible to get it if Jack stands beside it, facing away from it, and then bends down. He picks it up with his feet!
Alternatively he can face the coin and then bend down until he does pushups - he'll get it that way too.