Not a priority I would say, if you have the gels it's more worth while to upgrade the bolts themselves. Okay I pulled up the list in front of me now:
TOP Priority, get these asap in any order of your choosing.
- Max Sprint time - MIN Lv 3 (I find that Lv 3 is bare minimum/ good enough for me)
- Revolver - MAX accuracy and MAX Crit (These two are amazing at +50% critic you're oneshoting every other common enemy. You're not going to be using this against bosses so I would pick crit over damage, the final Crit upgrade cost a bomb so don't worry about saving it till later)
- Flash Bolt - MIN Lv 3 (It may not seem like much but flash bolts are my favorite bolts. They are cheap to make, stuns enemies and open them up for a stealth kill allowing you to save ammo, they also reveal hidden enemies. Upgrade them to at least Lv 3 which would give you just enough time to stealth kill 2, maybe 3 enemies with one flash)
- Harpoon Bolt - MAX (It would cause a bomb to invest, but at Lv 5 the Harpoon would be your highest damage dealer for how cheap it is to make. And it also has a flame tip, allowing you to ignite oil pools and set enemies on fire.... highly effective against a certain boss)
HIGH Priority, do this inbetween maxing out your top priorities and these are in rough order:
- Matches stock
- Syringes stock
- Handgun stock
- shotgun stock
- Bolt stock
- Sniper stock
- Grenades stock
Basically this is a survival horror game in it's purest form, that means resource management is key. Stock up on EVERYTHING. Eventually you'll want to increase these to the max, prioritize whichever weapon you use more but I find the first three most plentiful in the beginning so there's a high chance you'll reach the max limit early and is forced to leave them behind.
Situational:
I recommend damage and reload time for shotgun and sniper if you choose to upgrade them. Mostly because these are your heavy hitters that you'll pull out for tough enemies, and you can't headshot instant kill those. For Magnum go for Damage and accuracy.
Upgrading your health needs no explanation but note that when you upgrade, it also heals you to that max. So if you find a safe room at 30%, upgrade your max health would also heal you to full. So use this tactically.
Syringe recovery as well, you can't go wrong with it.