Is this a decent gaming laptop?

Well your loading overall will be pretty slow since it's 5400rpm hdd. The video card is pretty decent for a laptop. I don't know much about laptops' pricing but I think it's an all right price http://shop.lenovo.com/ca/en/laptops/lenovo/y-series/y50/ you can always try the $1000 version of the y50. The video card is slightly better with 1tb sshd.

not strong in laptops hardware, but it feels over expensive...

"Gamin laptop" is just marketing phrase for gullible.
If you need laptop, its not for heavy calculations but more accessibility. If you need gaming rig, always get custom build PC. If you need for work, for presentations, remote access, and any other low process intense job laptop is fine, but how things are advancing, soon large screen tablets will take-over that job.

First of all - playing AAA games on laptop is now in most cases the matter of settings. On a core i5 ivy bridge, with Geforce 630M I managed to get 60 fps in almost every game. I tried to run Battlefield 3 and 4. Need for Speed: The Run. To The Moon. Bulletstorm. This War Of Mine. Batman: Arkham Origins. Crisis 2 (it was so boring that it lasted about 15 minutes on my hdd, and I won't buy any other crisis for more than 0,99$ - which probably means that I won't buy them at all) L.A. Noire. The Vanishing of Ethan Carter - I hit 60 fps on every single one of them. Sometimes in lowest details, or in sub 720p resolutions, but still - they worked. I only failed with Max Payne 3 (30-40 fps) and FFVIII (15 fps in battle, 30 fps on world map, it was still playable)

So will this laptop run most modern games? It probably will. But it might require lowering details. And what is wrong with this laptop? First of all - graphic card memory. GDDR3 and GDDR5 are not in the same league. Also it is more probable that it is really only DDR3 (as far as I know GDDR3 are not used in this graphic card, but it is shipped with DDR3 - but I might be wrong) Which is even worse for graphic card. The difference between 850M and 860M isn't very big. It just about 10-15% more power, but 860M is always shipped with GDDR5. Also this 10% more power might be useful, but it is not worth extra 100$. (and this is usual price difference in many shops between 850 and 860)

HDD in this rig will in most cases just increase load times in modern games (because they are still optimised for PS3 and X360 - which means that streaming textures were at one point prepared to fit in 512 or 256 MB RAM - and even 5400 rpm HDD will manage to load them just in time) But as more and more games will jump to current gen consoles, and when they will start using again all these memory saving tricks it will significantly increase load on HDD, and faster HDD might make a difference in a year or two.

Also the heat problem is significant, cooling pads usually doesn't work properly, and just increasing clearance between desk and laptop is usually a better choice.

Lol,here's a overprice because of "Mega-Alluminium" and super "IPhone-like touch screen",I think you don't need both of this gay things to play AAA games.
Better find something productive,effective for this price,I've bought new Dell Inspiron 15 3000 series and that's quite same as listed for 500$,I have a cheap plastic hull but good inner resources xD
And I still haven't seen any probs with overheating,but I see it on my friends' Lenovo laptops everyday =\
If you look better - you can find the best option for your money,especially because you can use web-shops which I couldn't.