One of the more fun brainteasers. Spent about 3 hours sorting blocks while waiting, doing some stuff in between and then returning. Got to 22 lvl. It starts to get tedious there. Sorta want more items or threats that will allow to speed up the play. Maybe a pair of portal blocks that can be undug and moved to allow access to block dumping area. Maybe with a fat cooldown. The springs sorta give inconsistent access to some areas. And maybe some rare blocks being spiked, while being available for pickup requring extra space to manage them carefully.
But it's really fun so far, just replayability dwindling.