This is a mod that has been around since the dawn of minecraft modding. Back in the day, you installed ML/MLMP/Forge (which wasn't what is is today), then dropped in Buildcraft and IC2, then decided what addons you wanted to use. It was that ubiquitous. Of course, it was also a royal PITA back then, before even the Technic Launcher existed. We had MagicLoader, and I think MMC was around in some form or another, but that was really about it. So. Why was this mod so enormously popular, and what positive things can we take away from this mod? First off, it literally invented an ore refining process beyond 'put ore in a furnace'. Every single ore refining process from every single tech mod out today stems from this one innovation. However, it did that because it NEEDED such a stupid amount of metals to get going that you pretty much needed ore doubling to get anywhere with it. So while it increased your ore production, it exponentially increased your ore consumption, which ended up in actually requiring MORE mining, rather than less. So it didn't just go 'lol, let's do 5x ore processing', it balanced what it gave you with what it consumed to create your manufactorum. This is something that certain tech mods these days should take a more serious look at revisiting. Second off, the tools and armor. In particular, let's talk about the drill. It goes through both pick blocks and shovel blocks, but consumes energy, and the energy storage it had was decidedly finite. So either you wore a batpack (which means no chest armor), or you were coming back up out of the mine every five minutes or so to recharge it. Again, this was balanced. It also required a significant quantity of resources to create, and a certain amount of infrastructure to support the creation and usage. That drill, that one tool, was a simple, elegant, and profoundly useful tool. Probably the epitome of 'useful but balanced tool' that I have ever seen any mod produce. The chainsaw was another good tool. It was an axe, that could shear sheep. My kid never stopped giggling when I would sheer sheep with a chainsaw. But with old-school Forestry, by the time I could get a chainsaw, I already had a tree farm going, so it didn't have such an enormous impact on my play-style as the drill had. If I had ever wanted any tool that TiCo never was able to provide me, it was a tool which could go through both pick and shovel material equally. Given access to a drill, I would actually forego TiCo pick and shovel for it. I'd still use TiCo for other tools, however, so it would still be viable. But I never did get a good replacement for the IC2 drill. Now let's talk about some of the design concept that are perhaps more open to question. There was the power system, which had both a lot of very good things and some less good things about it. Overall, it was positive back in the day before the advent of RF. Back then, there were two main types of power: MJ from Buildcraft and EU from IC2. Everyone used one or the other. There were several means of converting one to the other, although typically there was some understandable loss in the conversion process. EU introduced an excellent concept about energy loss over distance, which was, in and of itself, not a bad thing. The other thing it introduced were packets and voltages. Energy loss was per packet over distance, so while higher voltage lost more power per block, due to the fewer packets involved, it actually ended up more energy efficient over the long run. The 'explosions on too high a voltage' thing was on the punitive side, but it was the price for doing business back then, because there were no alternatives. These days... I think this is a feature best left in the past. However, the IC2-ex branch used these days completely changed this, and I feel it was not for the better. I honestly feel, and will provide cogent arguments for, replacing EU with RF in IC2-ex, since they've done away with the one feature that made EU so amazing. After all, they've gone to a calculation matrix which is very similar. You can build in energy loss in the RF API, you can even build in explosions if powered by the wrong conduits with the RF API. You can do everything the IC2-ex brach does with EU with the RF API, and do it with more efficiency and compatibility. Bluntly, I'm not going to install a single mod that runs on its own version of power which I then have to convert to the power used by every single other mod in my pack. Either go back to the packet system or go with RF. The current system is the worst of both worlds. Another thing the IC2-ex branch introduced that I don't particularly approve of are the hammer and snips. More specifically, what I don't approve of is that they only have a hundred uses each before they expire entirely. This is the mod which gave us the drill, and now you are giving us a tool with the least durability of any tool in existence other than vanilla gold? Seriously? From a realistic perspective, one of the hammers in my forge is over two hundred years old, and is used quite frequently. Handle's been redone once in that time. This is just a blatant excuse for resource bleed for the sake of resource bleed, and entirely silly. At least increase the durability of the tools to somewhere around 512. When I spend more time re-making tools that keep breaking on me, in a mod most well known for creating indestructible tools, than I spend time making the machines... you know you have a problem that needs to be addressed. Mind you, there are some things the IC2-ex branch did right. The processing system needed an overhaul, and they did a pretty darn good job of it. It is complex, but it is able to be automated. Eventually. There are now more types of energy generation other than 'charcoal', 'lava', and 'nuclear'. And more than one type of nuclear energy production as well. Mind you, I'm not a big fan of how they kept swinging nerf-bats at things like the CRCS/DDoS systems. They should be encouraging large overly complex HAYOish systems, not slapping them down by implementing kludgy code to make things only able to cool in the same reactor they got heated up in (which is asinine, in my opinion). However, it's not like you can actually transmit that kind of power anymore either using IC2-ex, so there's no real point in implementing the nerf in the first place. Which is another source of grumbling on my part. So yea. IC2. It pioneered the technological frontier for modded minecraft. It had a lot of good ideas. It still has some that can be looked at. However, it also needs to either un-fix some things done to it, or just start over with a cleaner API, and also tweak a few things, before I'd be willing to touch it again.