I like to see into some levels special passages, have probability to give loot in 50% chance. They contains some destructible blocks, chained to ghost block & queue of solid blocks. They overlap path, so player decides - destroy some blocks, breaking chain & go to appendix, then loot may be given normally, but may be blocked with indestructible wall. This wall cannot disappear, because of chain connected to ghost block's broken. However, if player hits ghost block first, it can remove wall, but if loot crates was touched to wall (variant 1), it'll disappear too.

So i suggest to additionally provide some thimblerigging-game like passages.
this is a scheme
Legend:
white - floor
grey - gaps
dark yellow - borders
black - indestructible block
red - explosive block
blue - ghost block
purple - ONE explosive block must be located on RANDOM selected slot
green - loot crate
P.S.: purple blocks must be placed out of vision range & far enough to prevent hitting it by anything, including vases & potions.