You’ll need to craft two upgrades early on in order to progress the story (one is a solder upgrade for your glove and the second, a bit later, is the plasma blast to open doors). Materials are dear, there’s not many to spare in the game so it’s worth poking around each area looking for nooks with extra materials, it’ll save a lot of backtracking late game.
Eventually you’ll want all upgrades for completion, see
but just to recommend the early upgrades that help the most:
Running upgrade
Gunk sucking speed upgrade
Gunk sucking area upgrade
Finally, the Plasma Blast upgrade that kills small gunk creatures is really nice for stunning Gunk Spitters and Gunk Beasts (has a skull icon on it), you unlock this a bit later, save materials for it, it’s your most useful upgrade.
I never deployed a trap even once in the game. Avoid until you can craft everything.
Upgrades are unlocked by scanning new things, you should be following a scanning guide to avoid backtracking anyway. See:
The Full House achievement in The Gunk worth 132 pointsScan every scannable type of objectOtherwise, as the description says, you get this once you’ve crafted your 5th upgrade at the workbench on your ship.