Penumbra: Overture in a nutshell - first-person FPS-style view and controls, but with no firearms, and gameplay is mostly occupied with adventure game puzzles. Fairly frequent encounters with stock "survival horror" monsters, which emphasize stealth to sneak around them because the game limits you to rather poor bludgeoning weapons. A very unique "physics engine" and system of interacting with the enivronment, but one which also can be very clumsy and hamper the game as much as add to it.
You play as a young man named Philip, who receives a letter and a bunch of documents from his estranged (and now deceased) father. His father's last wishes are to have the documents destroyed, but Philip of course pokes through them and gets curious about them, following their trail to an abandoned mine in remote Greenland. After falling in the mine and getting trapped by a broken ladder, Philip is forced to press forward for the sake of survival, slowly unraveling a complex plot full of monsters and netherworldly horrors and etc.
It's not totally accurate to call the game "Half-Life 2 without guns", but it's really not far off the mark. Basically, you manipulate items by holding the mouse cursor on them to "grab" them with the left mouse button, then moving the mouse in whatever direction to pull, push, swing, rotate, throw, etc. Kind of like using the mouse as a ghetto Wiimote. This mode is toggled by tapping a key to fix the camera view in place when desired, so that you aren't using mouse look and object swinging at the same time (though you have that option as well, and sometimes have to use it.)
The game's opening tutorial mode quickly demonstrates the good and the bad of this engine. Philip is tossed out into a snowstorm in Greenland, lost and slowly dying of exposure. To enter the mine, you have to pick up a rock, carry it to the entrance hatch, and smash a bunch of ice holding the wheel in place by actually swinging the rock at it via the mouse. That's the good bit. The bad bit is when you go to turn the wheel and find it fiddy as all hell, seemingly requiring precise positioning and sometimes seemingly sheer random luck to actually move the way it is supposed to.
There's also some oddball design decisions soon on display when you get into the mine and begin poking around. First of all, you can't save when you want to. The game only lets you save at pre-determined points, and auto-saves when you cross them. As you'll find out later in the game, some of these are really not placed thoughtfully, and can auto-save (and ruin) a game at an excruciatingly bad moment that it's almost impossible to navigate out of. The very first save point takes quite a while to stumble to, and isn't very evident when you find it, so this can lead to a lot of replaying of the tedious introductory bit while you try to figure out the designer's arcane mechanics.
Philip has only a limited flashlight (battery power soon runs out, new batteries are exceedingly rare) to guide him through the almost totally unlit mine, and a glowstick that never runs out but only lights the immediate area. As you'll soon find out however, the flashlight is next to useless because a) it runs out so fast and can't be replenished for epic stretches of time and b) if a monster sees any light from it it cues them in to your location. The monster AI is actually one of the high points of the game, they're fairly intelligent about using light, noise and other environmental cues to track you, and if you encounter more than one of the same species at a time, they'll use some rudimentary "squad tactics" sometimes to outflank you and more effectively enjoy your deliciousness.
The downside of this? Since combat with monsters is next to impossible to win thanks to the clumsy weapon swinging mechanics and Philip's noodle arms, the only means of traversing an area often requires hiding tediously behind a stack of crates for upwards of 3 to 5 minutes until the monster gets done snuffling around the area, then moving to another crate stack and hiding for another few minutes until you can get a clear break. And of course, if there happens to not have been a save point near recently and you get sniffed out somehow, get ready to re-do these tedious sequences multiple times.
Other bits of weirdness draw you out of the game. The game is decent about explaining mechanics in the early going, but there's a key one it doesn't bother with. When you crouch, the screen goes all blue around the edges, and coupled with the heavy panting and grunting that Philip does whenever you attempt anything verging on exercise, it initially appears you're taking cold damage or something. But what that really is is the oddball "night vision" mode, which helps you see farther in the dark ... but only when you're crouched and not moving, if you stand and move at all you completely lose it. Initially you find some tempting barrels to smash, but the perfectly good lead pipe found nearby is refused as a tool to do such things (and you get berated for "thinking crazy" for trying to use it that way to boot), and you have to wait to find a hammer to be able to break stuff. And at the outset of the game, the way forward requires you to go through a sealed hatch which something heavy and snarling slams into and nearly cracks. Now who in hell would actually go in there for no other reason but curiosity? The sensible option would be to drag heavy objects over the hatch, seal the room back off, and wait for the weather to turn to go back the way you came, but of course that wouldn't make for much of a game.
The lattermost is a problem because identifying with a main character is a big part of a horror game. Playing in Clock Tower as a nearly defenseless 14 year old girl draws you into the experience more, because psychopaths aside, no one wants to see little girls get butchered up. Philip comes across as weak, kind of a twat, and completely responsible for his own downfall right from the beginning, so when a hellhound eats him up you're just kind of like "meh, no great loss to the world there."
The game also hits a major problem common to horror games - once you've seen the initial "pop-outs", and get a feel for how the monster AI works, the game really loses horror value in a hurry. It also doesn't help we've got a small collection here of the same old tired survival horror enemies - demon dogs, giant spiders, etc.
The sound and atmosphere are great, and the general concept of the physics engine is interesting, but the game just makes too many mis-steps and never congeals into something really good. Though I do give Frictional props for releasing the game as open source when the Humble Indie Bundle got into the millions, I guess if you've got the programming chops you can go mess around and fix the game yourself if you want.
* Gameplay Video