I tried to play this when it first came out, and was too stupid to make it through the demo. Just plain dumb on my part, not the game's fault. Giving it a shot now, and all my clickyclick adventure game and turn-based game skills and FPS skills won't help a tinker's damn.

I have only a tiny bit of battery power, I gather that's because I haven't bought bigger shield batteries, but they haven't yet been for sale at Weasel. "E" supposedly turns on and off shield, but instead it uses any batteries I have to recharge. Occasionally I find and pick up an item called an Ionic Shield, which doesn't appear to recharge me *or* stay in inventory, just vanishes. Do I have to turn shields on manually? Is it always on? Are the better batteries and shields available later? Or do i just suck at this game? Also, after I fail to beat this I'm going to dig out an old horrid knockoff of it called "Meat Puppet" and play it with cheats and see if I can beat it. When I played it when it first came out and I got a review copy (that's how long that's been) it crashed to windows immediately.

Better batteries become available later (both sold and found). Better shields also become available, although these are completely passive- you won't see them in your inventory once you pick them up or be able to actively use them, but you'll definitely notice the effects in terms of survivability. Shields are also always on, and will absorb some/all of certain types of damage (depending on what kind of shield you have).

The shield is always on and doesn't suck up any power unless you're hit by something from which the shield offers protection. Some enemy weapons bypass the shield and go straight against your health, while there are some other things that hit both shield and health at the same time.

You'll get better shields eventually. Not sure why they made a bunch of extra level 1 ionic shield gens for you to pick up since you can't drop it once you have it and you start the game with it. In other words, picking up any more ionic doohickeys is pointless. Adds flavor, I guess. Later on you'll get energy weapons that use the same energy source as your shield, so firing those weapons reduces your battery power a tiny bit and thus your available shield capacity. I typically used the energy weapons only against very specific targets so the power drain didn't present much of a problem.

You'll actually find two upgrades related to this (DarrkPhoenix mentioned these): shield generators and batteries. The red item you pick up and use to charge your suit's battery is called a "power cell" (this comes from additional manuals that came with the retail version and are not included in GOG's package for one reason or another - ask EA why they aren't in there.). A single power cell will recharge about a third of the battery, regardless of what type of battery is installed in your suit. Chalk it up to more efficient technology or some other such futuristic hoo-ha. In other words, when you get a better battery, you'll get more shield capacity (you can take more hits) and you'll be able to use your energy weapons more. Likewise, it won't take twice as many power cells to fully charge your current ("current", get it? Bwaaahahahaha!) battery even though it's giving you twice the power capacity.

What I recommend is getting intimate with the roll keys (IIRC NumPad 1 and 3). These let you pop in and out of the LOS of the bad guys so you can fire off a few shots without taking much return fire, which reduces the need for battery power for your shields. This is also an important maneuver to use when trying to time the security cameras.