I hope this does not count as advertising, if so please delete this.
I have written a few game reviews:
Arcanum
Gothic
Gothic 2
I'm also planning to do some mod reviews, I am currently open to suggestions.
I plan to do a review of the Oblivion mod "Nehrim" when it is translated into english.
Nehrim
Any other recommendations/suggestions would be most welcome.

One suggestion would be to post abbreviated versions a user review for the game here on GOG (without links to the full thing, of course). That might be of more help to GOG users looking to buy.
As for mods, one (non-GOG related) mod I'm avidly watching is the Dear Esther overhaul by Robert Briscoe, one of the people responsible for Mirror's Edge. But this looks a lot, lot more impressive.

Read the Arcanum one. I own it but haven't played it yet (it's in the pile) and found your review concise and to the point. It held my interest all the way to the bottom of it.
There's a small grammar mistake I think, on the first line of the fourth paragraph where there seems to be an extra or unnecessary "is it" (...that is it contains...). Other than that it all seemed fine. I bookmarked it to keep a link to the high res and unnoficial patch. I'm assuming the GOG version can have both of those installed without a problem.
I really liked that there were virtually zero spoilers and most of the "cons" were technical things that don't really ruin anything from the plot. Good job.

EL_Caz, there's a great thread Here in the Arcanum forums that gives detailed instructions on adding mods to the game.

I like your reviews. They're informative, contain little to no spoilers, and seem unbiased. I'd like to see more reviews from you.

^^^^^ SECONDED ^^^^^
Your Arcanum review was right on the money with no spoilers and actual smart CONS section. I would love to see more.

Thanks very much for the kind comments guys.
I will write some more content shortly.
@El_Caz - Thanks for spotting the mistake, Ive fixed it.

Look, it's not as if I could do much better, but I can see lots of room for improvement. First of, fluidity. The thing with fluidity is that it's hard to explain, you have to read it to feel it. For example:
The game begins when you(the nameless "hero") are thrown into the colony for an unspecified crime, you have been provided with a message which you have to deliver to the mages in one of the camps. At the beginning of the game, you are weak and will have your ass handed to you by any passing creature, your character has to learn to survive and develop in this brutal environment, although you have the freedom to go anywhere you wish, this is not a hand holding RPG with level scaling such as Bethesda's Oblivion, some areas contain some very strong enemies and if you are not strong enough, you WILL die.
Here's how I would rewrite your paragraph:
The game begins when you, the nameless hero, are thrown into the penal colony for an unspecified crime, and have been provided with a message which you must deliver to the mages in one of the camps. At the beginning of the game, you are weak and will have your ass handed to you by any passing creature. Your character has to learn to survive and develop in this brutal environment and although you have the freedom to go anywhere you wish, this is not a hand holding and level scaling RPG such as Bethesda's Oblivion, as some areas contain some very powerful enemies and if you are not strong enough to face them, you WILL die.
The thing with great writers is the fact that they know how to form sentences so that they can guarantee fluidity and avoid over repeating words. To combat this, try to implement variety of words into your reviews. I don't want you to feel like I'm trying to beat your writing down, it's just friendly advice. It's not the best of examples, but I hope I've made my point.
Apart from that, I think it's great that you're trying to get some awareness for these games out and the way that you're doing this is solid. Short, to the point, and with pros and cons tastefully implemented into the review. My opinion is, if you refresh your writing, it's gonna be great all round.

Okay, a few more thoughts now that I've had a chance to do some reading. Mostly this is constructive criticism so I'm not going to concern myself with the positives too much as you're already doing those things right.
- The explanations in the first paragraphs of both Gothic 2 and Arcanum contain relevant information, but they're not really well suited to opening paragraphs of a review. Essentially they're not giving the reader a good first impression of what they're in store for as it reads like something out of wikipedia. The intro to Gothic is a lot better.
- Reviews should be factual and as unbiased as possible. Yours come across well as being such. But they can and should make for entertaining reading wherever possible. I would include mention of things you experienced in game.
Given that they're all fairly open games you could try to do something fairly unexpected and see what the reaction to that is. Again your Gothic review is almost there with your description of the Old Camp. For instance, you could mention how you tried to deal with these lowlifes. Where there other ways of dealing with them that they didn't offer you (like a knife in the back)?
- You should tie your opinions about the game to these experiences to make them seem more grounded. For instance, you could mention a particular fight in Gothic 2 as an example of how the combat system is pretty lousy. That way you're not just stating your opinion but explaining why you think that, and in a way that involves the reader more.
- Avoid using "quotation marks" so much as it reads like the equivalent of pretentious people's gesticulation when using terms they don't agree with.
- Including screenshots is a good idea. But maybe also throw in some captions. Either humorous or at least explaining what's going on in the shot.
- Include a breakdown of the various factors you take into account when reviewing the games. What things do you consider most significant? This is important to maintain objectivity.
- Titanium makes some great points about fluidity. I'd pay heed to those too.

Thanks for the feedback.
I shall attempt to improve on some of the points raised in future reviews.