Sorry to respond to an old post but I just found this community. For the turrets I’d say definitely get the faster build upgrade if you’re running two turrets. I use dual turrets with the range upgrade (that restricts their movement) and put them against a wall on a platform or facing each other if there’s no walls handy. Once you put the turrets on a platform, break the platform and you can refill them while standing under them. Running two turrets gives you highest DPS but also uses ammo a lot faster, so pick single turret or only put down one if ammo becomes an issue.

Sometimes you can find a moment to throw down turrets if the shit hits the fan but it’s a lot easier if you try to think ahead and strategize. I’m dogshit at strategizing and chess but you pick up knowledge along the way. If I reach the mouth of a new room I usually throw down one or two just to preempt the “wave” of bugs that spawn with the map. About to repair a lost mule? Throw down turrets covering it first, that spawns bugs. Same for dealing with lithophage spikes. Scout starts screaming about a detonator in the next room? Back up to hopefully a nice long sightline and put some turrets at the end. How I play it, sometimes you’re luring the bugs into the turret trap with your dwarf as bait.

If you’re on PC, the SimpleQOL mod has a feature that will auto-recall the turrets if you get a certain, user-specified distance away. It’s nice if you’re always forgetting about your turrets but can get in the way if you’re trying to leave your turrets covering a teammate or something and go to another part of the cave. I don’t use the auto-recall feature any more but have definitely found myself facing a swarm with my turrets set up 100m+ away.

Engi’s second secondary unlock, the Breech Cutter, is crazy powerful. With the Born Ready perk you basically never have to reload it, just switch to it, fire off a few beams and melt an entire swath of bugs, then switch back to primary and repeat. If you hit a rockpox bug just right with the beam you can hit most of the weakspots in one go. Born ready perk is also super useful for your platform gun, keeping that loaded gives you a better chance of a way out of sticky situations.

The lure grenades (first one, I believe) can really save your ass in some situations. If an oppressor (or worse) shows up near your salvage ops uplink or comes down your escape tunnel with no way to hit it, lures can buy you valuable time or maybe expose the weakspot if bug pathing allows. I personally run the shredders grenade just because it’s newer and fun.

Also, the platforms are one of the coolest and wackiest movement tools in the game. You can do so much shit with them. Building stairs and making platforms to jump down on (only with the fall damage upgrade!) are great, but you can also patch holes in the floor to prevent nasty falls or even block off whole passages by stacking enough pancakes in it. I’ll usually seal off the ceiling holes that resupply pods leave to keep bugs from crawling through. If you need a little height boost with no wall nearby you can jump and fire a platform at your feet, it’s expensive and doesn’t get you very high with each platform but it can work if you’ve got platforms to spare. Fighting near a cliff-face sucks and gives you little time to react to the bugs that pop up over the edge but if you’ve got some setup time and platforms you can make a nice shelf that will force bugs to come into view farther away and give time for your turrets to tear them up.