Lack of side-contents
Meezle Deezle
The game could use more things you can do in the Machine like farming, variety of food with certain buffs, extension upgrades to the machine like deck expansion/multilevel. More usage of zipline deployment from the machine as a form of transportation back and forth like flares with limited reach. Some QoL like grappling hook to easily scale some certain heights. More weapon types are relative to the difficulty in a chest that isn't craftable to incentivize players to explore and do more POIs than mindless grinding for materials.
Dan Cz
After finishing the game. I'll agree with chest content relative to the unlocked or types of tools that you've already acquired. This goes both ways though. Let's say, add unique weapons that can't be crafted (Named weapons, with extra stats that aren't too op). I think the game needs a distinct tier system to organize each weapon levels, for example, (T1 consists of wooden and stone, then T2 will go above copper level and so forth.). This would improve the user experience for me, this can be applied explicitly or just as a subtle UI update anyway.
Fishing is also a nice addition that the player can delve into while the machine is in a stationary mode. Regarding the machine upgrades, expansions like additional decks, size changes or even inside compartments are a nice content update.
I'm also assuming that additional monster types will be added so that's a given. I think these are all the points I can suggest for the next content update.