Immersive Engineering is a tech mod with a certain charm, based on the ideas and concepts, and with most assets created by Damien Hazard.
Overall, it's about realism-inspired technology:
Instead of glowing red tubes, it offers actual, hanging powerlines.
Instead of one block that magically spits out dusts when ore is put in, it offers a crusher, a big multiblock (5x3x3) that features rotating wheels and spits out particles as it breaks the ore.
Instead of a Laser that turns power into magical light and ores, it offers an Excavator, another massive, resource intensive, multiblock (3x7x8) which digs ores out of the ground with a big rotating bucketwheel.
IE is about making tech mods more balanced and more pretty, and adding its own twist by going for retro-futurism (think BioShock, Order 1886, SkyCaptain and the World of Tomorrow) rather than clinical white+grey future cubes.
It uses the RedstoneFlux API, known from RF Tools, BuildCraft, EnderIO and many other mods, but can be played fully standalone. Unlike other mods, IE does not use powertransfer via lanes of blocks, but instead via cables spanned between connectors.
The mod features Power Generation in forms of waterwheels, windmills, biodiesel and more and many of its machines are multiblocks!
For all your documentation needs, you should look into this mods ingame documentation, the Engineer's Manual, crafted with a book and a lever.
Go wild, as long as you do not monetize content that doesn't belong to you and abide the EULA ^^
And obviously, report your bugs on the issue tracker! :D