Unlike some I have no problem with G.O.G's releasing new games by smaller publishers that otherwise most of us would never discover and all so far at an affordable price (The Witcher 2 being the only exception but still good value for the special offer price that I paid and now supplying the enhanced version at no charge).
However, it would be great if we were also offered trial versions of these new games I appreciate that this would not be possible on the old games but being old most have many good reviews to help guide choice.
Playing a small part of a game is the only way to get a feel for the story and mechanics and decide if the game is truly what you feel you are looking for.
G.O.G. Has allowed me to diversify my taste and buy many affordable games I have never heard of before of many of types I might never have even considered buying, based purely on reviews. There have been a few turkeys for me but, as I buy mostly the lower price or special offers that has been a small financial gamble.
For example, Spacechem looks like it might be of interest to me but different enough for me to feel a trial would be necessary to decide so, I am tempted to buy either 1 or 2 older games for the same price.

There's a feature wishlist.

Also trial games would need DRM.

About SpaceChem, there's a demo.
http://store.zachtronicsindustries.com/product/spacechem
On the right, for Windows, Mac, and Linux.

So you're essentially asking for demos to be available on GOG? Yeah, that's not a bad idea, although they tend not to be hard to find anyway.

And a lot of Demos for GOGs are linked at the Wiki:
http://www.gogwiki.com/wiki/Demo_Links

I did not realise that, thank you for the information

I think maybe I am being very unfair with that statement I buy a lot (for me) of G.O.G. games based on reviews or having owned them previously however, I am now in the position of not really having the time to work on them as some have a big learning curve such as the simulator style and many just take a while to get into, I would not dismiss a game after only 10 minutes of play unfortunately because of having a number of games from G.O.G. plus from other sources (some of which remain still uninstalled) and limited time I find that if a new game doesn't grab my interest quickly I will go to another. As you do I buy the games because even if they are not the type I usually like they still look interesting and at the price are worth the risk.

If i want to know if i li9ke the game i look at a lets play on youtube the start isnt a spoiler anyway but then I know if i like the basic.

I have tried doing that but find watching someone else play bores me very quickly partly because I might not play in the same way and it is a very different experience from actually playing. Yes, it will give me an idea of the game mechanics but not the immersion of actually playing.