Before you dive into the game, or at least hit your first upgrade units, you ought to have an idea of what you're going to allow yourself. It's possible to beat the game with nothing but the wrench on Impossible, however, if you want to know more about what all the upgrades do, read on.
A must have! The stronger you are, the faster your enemies die, the less chance they have to fight back. Plus you can tote around more stuff. Value getting this upgraded to level 6 over anything and everything else.
More hitpoints are always a good thing. However, I'm a bit iffy on upgrading it a lot right away. On Easy, you have enough hitpoints to survive a nuclear explosion when you start the game, and on Impossible, almost anything will kill you in one hit anyways. I'd recommend only upgrading it a small amount until you head into the BOTM, where there are no resurrection stations.
Depends. If you use the Worm-Mind implant, 1 out of every 4 points of damage you take is taken from psi points. However, at the very least, you also need research skills of level 2, (the LabAssistant implant will get you research skills of level 3, enough to research this) so if you don't plan on research skills, you don't need this either.
Speeds up both your movement speed and the speed you swing melee weapons with. Doesn't increase the damage they deal, but I'd recommend upgrading agility stats before facing cyborg assassins. Level 3 or so should be enough for you to keep up with them to kill them, I'd recommend getting this upgraded before you start upgrading your endurance stats.
- Cybernetic Affinity
Unless you're hacking, which this skill compliments, don't bother with it.
Quite useful. You can crack open security crates and get even more goodies to help you along the way, as well as disable security systems. However, you don't need it, there's enough ice-picks that you can do all necessary hacks with them, even on Impossible. It's your call here. It will be easier if you do get this, though.
Useless. There's only a few things I can think of that need repairing, and there's enough auto repair units to deal with them. Don't bother with it unless you don't want to give yourself access to hacking skills and want to get a useless tech skill during your tour of duty.
Can only be used on ranged weapons. Run very far and very fast from it unless you want to get a tech skill you won't use during your tour of duty.
You'd think this is useless, but it isn't. Maintenance skills allow you to store more power in the powered armor and implants. Since I consider the BrawnBoost and EnduraBoost implants necessary, I also consider this skill necessary.
Depends on what you want to do. You don't even need it if all you want to do is research the intestines of your enemies, and Toxin-A. The LabAssistant implant will allow you to do just that. However, if you want to use the WormMind implant, the shard, or perhaps WormHeart, you'll need it.
Despite the description of the wrench saying it doesn't require any weapon skills, it's actually a standard weapons, thanks to d0om for correcting me. It doesn't seem to change the damage the wrench deals much, but it does help. On wrench only games, you need all the help you can get.
Level 4 is necessary for the laser rapier. It's pretty expensive, on higher difficulty levels you may want to wait to get the shard, it gives you more bang for your buck.
Not useful for melee weapons, therefore not allowed.
Level 1 gives you access to the crystal shard. Upgrade this to level 6, and anything organic, (yes, even rumblers and psi reavers) will fall within 2 or 3 hits. If you get the shard, max this out, and you'll be a deadly killing machine. Most of the weaker electronic enemies, such as cyborg assassins, midwives, and turrets, will fall to one overhand swing, or two slashes, but the robots won't.
There's only 4 of these upgrade units to use, so you should know what you're going to get ahead of time. Here's a list of all of the upgrades, and my recommendations on them. However, it should be noted I haven't tried most of these, I'm judging by their descriptions their usefulness.
|Strong metabolism||Damage from toxins and radiations reduced by 25%||There's far better upgrades to get than this, and the hazard suit will protect you far better than this. Don't bother with it.|
|Pharmo-friendly||Extra 20 % benefit from all hypos||If you're playing on Easy and want your med hypos to go further, this is for you. On a higher difficulty level, you probably won't want this, because you won't have enough hitpoints that need replenishing for this to be worthwhile.|
|Pack-rat||3 extra inventory slots||Are you kidding me? We're getting our strength skills maxed out as soon as possible, this is so completely useless.|
|Speedy||Movement speed increased by 15%||You probably won't ever need this, since we'll be upgrading our agility stats.|
|Sharpshooter||Damage dealt with ranged weapons increased by 15%||*cough*|
|Naturally Able||8 cyber modules||*cough snicker cough*|
|Cybernetically able||Two implant slots||You can use two implants together using this, this is on my list of must haves. EnduraBoost + WormMind implant and hitpoint worries on Impossible are almost completely gone.|
|Tank||Increases maximum hitpoints by 5||On Impossible, I'd highly recommend this before descending into the BOTM. Hitpoints are hard to come by and 5 can mean all the difference.|
|Lethal weapon||Increases hand to hand combat damage by 35%||Not only is this on my list of must haves, I'd recommend getting it first. Pipe hybrids will go down with one hit no matter what, and they deal the most damage early in the game.|
|Security expert||+2 hacking skill if you already have hacking skills of level 1 applied to security systems||I wouldn't recommend this.|
|Smasher||Overhand swing upgrade||This, plus the lethal weapon upgrade, and you've got a dead shotgun hybrid in one hit. I'd get this at the second upgrade unit, in fact, I always do.|
|Cybernetic assimilation||You can extract a diagnostic/repair module from any destroyed robot and heal 15 point of damage||Never used this before, but reading the description, I'm a little curious about it. I won't recommend anything until I've tried it for myself, but it sounds like something you'd want to get at the upgrade unit in the mall, if you get it at all, because the most robots are found from there on.|
|Replicator expert||Items cost 20% less||You'll have enough nanites that you probably won't ever need this.|
|Power psi||Psionic burnout no longer damages you||Hear me laughing?|
|Tinker||Weapon modifications cost 50% less||How about now?|
|Spatially aware||Automap always filled in||Or now?|