A great story with an independant horror film feel makes Penumbra a story worth finishing...
Bear with me here, I love this game (im an adventure game nut that hasnt had a good fix in awhile until I found this gem) and I've played both this and its sequel both of which are great games. Forgive me for that, but I will try to be as true to my observations and not lead you down the road of just "This games great because I say so" (which, I have sadly done in the past and do not intend to do again).
Graphics: Im doing this first because while superbly fitting, the graphics are the worst in the game (or maybe, more accurately, the animation? Im not sure but I probably mean animation as well as details of the characters [how they're drawn]). I am able play these games first off on max settings so no I do not have a computer problem making them look funky, they just do and I think (thankfully) they honestly sacrificed a little budget from graphics/animation in light of gameplay and story which imo is a good thing for this game. Like I said though, I'm not knocking the graphics at all, they are fitting for what the game is, and to Frictional Games credit you could technically go through the whole game never seeing or barely glancing at the different nasty creatures that pervade the dank mine that will be your home for the entirety of the story. Everything, while not the best graphically, fits perfectly into the world they created though and really helps set the mood. In my humble opinoin this game is best played using only the green glowstick for light as well as lights around the mine. It helps make it even creepier (not that it needs help with that).
Sounds/Music: The low quality of graphics aside (trust me, they're decent enough for what this game is.. do not take those statements to mean otherwise) everything else in the game, to me is at the high end of the spectrum. For instance, sound. Not alot of games for some reason or other seem to care to much for their own ambience. It gets muddled in music and other ferocious sound effects. This game intends for certain feelings to course through, it is a horror after all and you need to be scared or at least on edge (I was on edge through both games) and have silence broken be a serious moment. The ambience in this game does what music does for most games. You'll hear a clank in the distance and wonder if something is following you or a growl to your left and wonder if you've been spotted. Its great how its done and if nothing else I can only say that I wish it didnmt always sound like everything was on top of you alrdy but rather around you. I played this with head phones on (another adding to the creepiness hehe) and noticed whenever a creature was nearby but maybe say, in the hall next to the hall your in, it sounded like you were right on top of it rather then the next hallway over. It added to the tension as you cant always tell if you've actually stumbled on a creature in the dark or if your just hearing them in the distance. Maybe its intentional, as I said it adds to the tension, but it seemed odd to me so I'm mentioning it. The ambience, though, is very good in this game and the music is equally fitting the mood but not over bearing. The music generally is very soft and almost non existant when your searching the mines and you'll know when something interesting is happening because the music shifts and suddenly its very exciting and intense. Thats generally your que to run for your life and really helps sell the tension of the game wonderfully. I loved it! In the words of a funny man: "It was vewy good"
Puzzles/Combat: Appropriate is a good word here. Thing of note though, theres a tiny bit of combat in this game which is more of a puzzle in itself because of the "physics" system they decided to use in combat as well. You have to actually move the mouse to motion the direction in which you swing. Not completely accurate or intuitive, but at least it doesnt get stuck at the worst times like AITD did. Overall, it was done well but the combat system has a purely afterthought feeling to it and honestly to me its unnecessary to have in the game at all in all portions except maybe one part and even then you dont technically need it, it just made it easier for me. All in all you'd be better off always running away (which they made it clear quite early in the story youd probably prefer to do that) or if your really better then me staying hidden.
Another form of puzzle in this is the hiding, btw, (terrible seguay... sorry) in which you hide in the dark very much like Chronicles of Riddick. While its great to see this in use again, and one of many options you have throughout the game in avoiding creatures, its probably your second best option when confronted with obstacles of deadly teeth caliber (combat being the third choice). Its second because while they'll teach you to do it early on (and it is definitely more useful in this then the sequel) you are just as well off running everywhere. Honestly you can just run past everything that attacks you but beware this option I chose as the best has its cost. First they can catch up with you easy, second you die fairly easy (its not unforgivingly easy to die though), and third they chase you until you block them or leave the area they are in. Whatever option you choose to use, choose what fits your playstyle. I chose in this one to hide sometimes and others run. Combat was an extreme circumstance choice I only had to resort to one time.
Lastly, the puzzles (the by nature puzzles that once you get past progresses you in the story, the reason we play these) are superb as well as the UI. Everything is done as if done by your own hand. I could nit pick it but its not necessary. You open doors by clicking and pulling the mouse to open the door. You open drawers the same way, and you turn, push, or open other various things the same way. Its very intuitive and enjoyable. The puzzles are that of logic fitting into this mechanic (Ala halflife... we knew it would pave the way for these types of games some day) and mostly puzzles are merely ways to get further in the story more so then doing a mini game to progress. Its old fashioned in some ways and very next gen in others to me and fit very nicely.
Story: I cant say much here or I'll spoil it. It's a creative and fresh idea the farther you go, always keeping you in the dark (heh excuse the pun), and I cant say anymore in fear I'll spoil anything about it. You'll have to play to make your opinoin on the story, but IMO while not entirely new of an idea, it is a remarkable ride and fun to play through start to finish.
Overall Gameplay/"Fun Factor": This game is fun. Hands down. I think even non adventure gamers would like this game for its well told story and intuitive puzzles- I do have a few quarrels with it, but not enough to risk ruining the story or putting down- and I can only say if you like survival horror this is a step into a new generation of adventure gaming that I am eagerly awaiting to see what more games follow in suit. You may want to play it if you havent already.