Croteam, after their hallmark series Serious Sam managed to create the first puzzler game on the level of Portal 2, which was unexpected, to say the least. After having played through the game, it is definitely my game of the year 2014 for various reasons, which I'll break below into several sections:
Plot
At the start of the game, you awaken as a android which is tasked with solving puzzles, for which Elohim - your maker, promises you eternal life. The story is told mostly through logs found in terminals scattered around the world, but also serve for communication with Milton, a library assistant and an intelligence with which you discuss some intriguing philosophical dilemmas. While Elohim encourages the player to explore it's creations, he explicitly prohibits venturing into the tower, which soars into the sky. As the story progresses, Milton encourages the player to act independently, and motivates him to enter the tower and find out the truth for himself.
Gameplay
The game starts slowly by introducing gameplay elements (some of which are unlocked by solving specific puzzles) and the difficulty of the puzzles ramps up pretty fast, but they are never unfair - even if some of them may be excruciatingly hard. If there is a situation where the player may get stuck, it's because some specific mechanics and uses of elements aren't expected or explained beforehand. Example: some puzzles utilize your own body for intentionally blocking lasers, which the player himself might not think for some time. One thing that may get on some player's nerves is the reset ability, which you will use at some point to unstuck yourself from an unsolvable jam. It resets the entire room along with all the progress you might have made, which can be somewhat annoying in longer puzzles which take some time to progress through. Once you do solve a particularly tricky puzzle, you are glad you persisted and managed to solve it on your own. On most puzzles there is a shrine you can use to get a hint if you get stuck (although some hints are too vague and don't help as you might expect), but getting that hint requires solving some hidden puzzles which are not a part of the main story, but are worth exploring any ways as they have the most beautiful locations in the entire game. If you find yourself a bit short on hints, you may want to play Sigils of Elohim, a free companion mini-game in which you may get an additional 3 hints.
There are four worlds in the game, which go as follows:
Mediterranean - ancient Greek/Roman themed world
Egypt - puzzles spread out in the desert, borrowed aesthetics from Serious Sam 3
Medieval - typical medieval style with ruined castles in a forest
Tundra - the "main" world in which the tower and the three other hub worlds are located
You start your adventure in the Mediterranean world and gradually unlock the Egypt and medieval worlds with puzzles, which are spread out into different rooms in every world. You can play the puzzles pretty much in any order, which is welcome if you are stuck in a particular puzzle, so the player can skip that particular one for the time being and return later on with a fresh approach, unlike in fully linear games like Portal.
Visuals
The game has some very nice visuals, particularly if you look at the texture quality (Example: look closely at the greek-style fresca scattered through the ruins of the first world, or just looking at the floor mosaic in the third world hub cathedral). There are some hidden locations with truly great visuals, so I definitely encourage anyone to explore the game fully, which will not go unrewarded. The game runs pretty well on older hardware, but don't expect wonders - the game likes stronger hardware, but it knows how to use it. If you played Serious Sam 3, you pretty much know what to expect, it's a visually slightly upgraded game, which is fine for my taste.
Sound
This game has one of the best soundtracks this year, which you can listen for free in full here
https://www.youtube.com/watch?v=0J2xolKQjs8It's one of the few games where I didn't have to turn the music off after some time as it blends in fantastically with the game. If you buy the sountrack DLC now, you might be a little bit dissapointed to find out that there's Elohim's voice in pretty much every track, making it a bit weird if you listen to the game's soundtrack in the public or at work. The game's developers promised to offer a versions without voiceovers, but we'll see.
Conclusion
I haven't had this much fun with a game in years, and Croteam did a stellar job with this game. If you like puzzle games, especially Portal 2, pick this game up immediately, you definitely won't regret it. For now the game the game doesn't have content beside the main campaign and the prototype maps DLC, but they shipped the game with the editor and full Steam workshop integration, and already the community started putting out stuff days after release, so we might get an abundant amount of content as time goes on.