So Factorio Extended Plus is cool, I like the way it adds to the gameplay but not to the learning curve, and makes the Upgrade Planner really worthwhile. I ended up with some balance / pacing notes after a couple of playthroughs though.
Gun Turrets 2 is a really strong tech.
Like, way strong. Gun Turrets 2 give x2 RoF and +50% damage modifier for a total of 3x damage output vs T1 Turrets, and at x1.5 range(ish). The Shattering Bullet Magazine does x2 damage over Red ammo, for a
total x6 damage boost to turrets available from a single & fairly accessible blue science tech, which is
just really strong.
The Shattering Ammo gives so much more DPS for so few extra resources that it's never not worth using as soon as you can. It takes 12 ore to make one Piercing Bullet Magazine (or 17 in Expensive Mode because steel), then just 4 more to double that DPS into Shattering Bullet Magazine. And some acid, but whatever, acid is cheap, 2 titanium & 2 copper is just a really strong cost efficient way of doubling red ammo DPS, you'll never not do that.
Gun Turrets 2 also gives the best-in-game shotgun loadout when Military 3 gives you the combat shotgun. This is a really strong combat power spike at
Blue Science, and also makes Vanilla Piercing Shotgun Shells completely useless.
So maybe Gun Turrets 2 could be reorganised as a tech, maybe split up, maybe recosted?
Mechanical engineer is a really strong tech.
There are so many things in that one tech, it's quite possibly worth splitting out into eg
- Research Engineer: labs & radar
- Metallurgical Engineer: mining drills & smelters
- Mechanical Engineer: assemblers (and centrifuges?)
Mechanical Engineer 1 also costing the same science colours as Automation 3 - and with no other intermediate products to research - makes it very accessible. Most of my playthroughs I end up customising an upgrade planner to skip either Assembly Machine 3 or Assembly Machine 4 because the Mechanical Engineer techs are just right there.
(And continuing the engineering theme, Oil Processing 2 could get rebranded Petrochemical Engineer, but whatever, just cosmetic.)
Turret research costings
Laser Turrets 2 and Flamethrower Turrets 2 are also blue science, which along with Gun Turrets 2 means that nearly best in game static defenses arrive ...
at blue science. That seems way too early in the game, and the only other later static defense upgrade is Uranium Ammo.
Also, these techs don't depend on later Military Technology ranks, which means someone new to Factorio Extended Plus poking around in the tech tree has more difficulty finding out what combat stuff gets unlocked later.
So maybe it's worth making T2 turret research take some more expensive science colours, and some other Military ranks as dependencies?
Expensive mode titanium
None of the "expensive mode" titanium recipes appear to have different ratios? Expensive mode manifests in vanilla via intermediates like cogs, steel, green and red chips. There aren't titanium intermediates ... so maybe Factorio Extended Plus expensive mode happens via ore conversion recipe in the Chemical Plant?
Given titanium gets comparatively small usage, and no science consumes titanium, the expensive mode ratio could be like 4 ->1 for that ore conversion, rather than the standard 2-2. This would also make the Shattering ammo types less outrageously strong than they currently are on expensive mode, even without recosting the Shattering recipe.
Underground pipe 2
The recipe for underground pipe 2 doesn't consume underground pipe 1. This means that having built a base, and then upgrade planner-ing the oil works, there ends up a pile of underground pipe 1 that just sits there not doing anything. Should the Underground Pipe 2 recipe use Underground Pipe so it doesn't just uselessly stockpile?