Invisible Inc is an amazing game. I've been playing it over the past 2 weeks, and the more I play, the more I like it. Currently have 45 or so hours clocked in the game, which is actually the second highest playtime of any game in my Steam library! It's also one of the most addictive games I have played in recent memory that keeps drawing you back for more. Those 45 hours were played in under 10 days.
Anyways, the gist of the game is that it is a punishing "rogue-lite" turn-based strategy game, with a heavy emphasis on stealth. It draws inspiration from XCOM Enemy Unknown and has got similar interface, but the core tactical gameplay is very different.
The game's campaign can be completed pretty quickly (on your first try on Beginner, you should do it in under 4 hours), but this game has been thoroughly designed with increasing difficulty levels in mind. From Beginner to Experienced, and then to Expert, you should get three complete runs at least, each offering a unique playing experience. Also, you will die a lot, particularly when you get to expert, so the game makes you learn from your mistakes to improve future runs.
I myself played the game on Beginner first, then after 15 or so tries I got through Expert, after which I played Expert Ironman and finally completed Endless 5/10 days in the same run.
The game's levels are always randomly generated. Initially, I didn't like this, cause sometimes you can be dealt an unfair hand and the level generated could be extremely difficult to traverse. But eventually, over time, you learn to deal with it.
There's an element of risk vs reward. Do you go slow, at the expense of your alarm tracker increasing quickly...or do you go faster, at the expense of being spotted by the enemy?
Even though I've played for 45 odd hours, there are so many unique combinations of augments, programs, items and weapons that the game has got an incredible room for experimentation. Since all of these are randomly obtained or bought along the way, you always have to adapt your playstyle, and as such, the game doesn't become boring or repetitive.
There are 4 different enemy corporations, each of them having a different unique threat, so that adds to keep the game fresh as well. There's also around 7 or 8 different mission types, and you have to make your choices count on which mission type to select, based on your needs.
When I played the game on Beginner at first, I liked it. Then moving on to Expert, I found it too frustrating to the point I was almost going to stop playing. However, once I cleared that hurdle and moved on to Ironman and Endless runs, I have grown to absolutely love the game.
Recommended if you like turb-based strategy like XCOM, and/or if you like stealth games, and/or if you like challenging games that punish and make you learn from your mistakes.