Ideas for multiplayer engagement
Emotes - Some emotes you could do like a thumbs up and thumbs down, like your player would do that on screen so when someone watches it they can see you react? Also hold up a sign or something fun, like unlockable ones?
Skins for Harvester - You could add skins for Harvey the Harvester that you could change by approaching them in the main hub!
Bow - Adding a bow would also be cool, you could maybe buy arrows from the equipment guy that do different things. Example you can buy explosive arrows and carry up to 3, they would take up your equipment slot like a the others do. But it would also shoot normal arrows like the bolt lancer one and break traps but not armor, so to kill a armored enemy you’ll have to make a good shot but you can take out traps to make it like a in between. Also haha it could maybe bounce off slanted walls?