Yeah, I felt it was a complete package and the time I played it was intense gaming. And I liked the humour.

But, if I had paid e.g. several dozen euros for it, maybe I would have felt I didn't quite get the longevity I'd expect for such a money, especially as the game is so linear that there isn't much reason to replay it I think.

Steam is currently asking around 9€ for it, maybe it is worth it, maybe not... I don't know how often it is discounted in Steam sales.

As a matter of fact, Portal 2 clearly showed that if Portal were any longer, it wouldn't be as good as it is. It's just about perfectly sized for what it is, so yeah, I'd definitely say it's rewarding.
Only played it on PC and yeah, the controls are not exactly ideal, but it's manageable pretty well. Only the infamous Meat Circus level is a bit annoying partly because of the controls; jumping off wall holds is notoriously imprecise on the PC.

All in all, the platforming is admittedly crappy, but the rest of it is wonderful. I'm not even sure why it is a platformer, to be honest.

In addendum, the window that shows Steam ads (which can be easily disabled) never shows itself when you first start the client, or randomly while it's running. But every once in a while (about every few days, or when there's a really special event going on) it'll come-up after you close a game. This way, it doesn't annoy you when all you just want to do is just play a damn game, and it can even serve as a pleasant surprise after your session. I've snagged a few games that were on sale because of it, which I might've missed otherwise.

Now, was I coerced into buying games I normally might not have? Maybe, sorta, technically, yeah, I guess. But it wasn't obnoxious, and it feels like it informs me of things I might be genuinely interested in.

And in further addendum -- at the risk of seeming like more of a Steam fanboy and apologist than I already am -- their recommendations page is a page you have to specifically navigate to in order to view. Implemented like this, it makes Steam's recommendations something you see only when you specifically feel like it, and as such, it doesn't feel obnoxious, and actually becomes useful sometimes (for example, your recommendations page will recommend a game if it's on your wishlist, and is also on sale).

Edit: Also, I am still technically on-topic, as per the following: I am immune to any and all criticisms of taking the choo-choo off the tracks.

I have it on DVD (it was in computer games magazine once). Played the first level, thought "meh" and never played it again.

I see, to be honest I'm new to the steam and GOG market, and I don't know how much the price tag varies but hopefully it will be available on summer sales. I would have finished "the witcher" by then.

Thank you again.

It's good to have another confirmation, thank you.

This game is simply amazing. I'm sure lots of idea and creativity poured into it. Each stage featured different objective, scenario and settings. I like it.

Over here! :(

But it looks awesome :(

Now that the giveaway is done (thank you Simon!) I'll respond to this.
I'm glad that your experience with Steam is a pleasant one, much like mine, but let's not get disillusioned here.
The always online requirement for many of the games that don't have offline mode is about as intrusive as it gets.

Also, need I mention in-game advertising? INSIDE THE FUCKING GAME?! This is something that I find intrusive, appalling and absolutely unacceptable.
And it certainly doesn't conform with your:
"Steam can just be that thing you use to play your games, with nothing shoved in your face to encourage you to spend more."

Citation needed. I'm not aware of any game with in-game ads delivered by Steam, but I'd love to hear your examples.

http://kotaku.com/220620/in+game-ads-coming-to-counter+strike-16

That story is five years old. Did it actually happen?

Yes, the official maps are riddled with massive, wall-sized ads. There's also one on the scoreboard. Granted, it's only ads for Valve games, but it's intrusive and immersion breaking nevertheless.

Probably the only way they could get a publisher to back it.

"An adventure game? Ha ha ha ha ha ha ha ha ha ha ha ha ha ha. Ha. Make it into a platformer, that shouldn't be too hard right?"

I apologize for my mocking tone. It was not meant as a personal insult towards you.

I do, however, find the caricature of Steam as a good and kind benefactor that has nothing but its customers interest in mind (In Valve, We Trust?) to be laughable as their entire business model is based on indenturing its client base. I'm also very bitter as someone who years ago was ready to buy just about any game, even if I had no idea what it was, just because it bore the name Valve; but now I have to to pass up almost every new release I have been looking forward to because they have Steam.

And for what its worth I did get my money back from the store in my earlier anecdote, it took a lot of yelling on my part to finally get the manager involved but I did get the issue resolved. That was Half-Life 2.