You can use stock assets and create impressive work, if you're willing to put in the time.
Of course, you will *ALWAYS* benefit from custom assets, but the reality is most people don't have the time, money, or inclination. I myself like to find uses for every model I have. Honestly though, there's SO MANY FREE MODELS out there from gameguru files, or the freebies section of the board, store, etc.. you really have very little excuse to use the absolute base model listing.
All of that aside, what's that got to do with 64bit?
Unlike a lot of you, I'm not a longtime FPS Creator user. I never used the product. I was a Lite-C and Acknex user and before that, good old GCS.
I invested in Game-Guru/FPSCR because at the time I was impressed by the inclusion of shaders at such a low price point. It was very difficult to find a shader-enabled engine that was under 300-800 dollars as an entry point. Over the years a significant amount of work has gone into adding additional features, and I'm happy with that.
64bit is important, as are other features. But we have to remember that Lee's a one man party.
I had an email convo with him this AM about adding a feature for plugin support to the GUI. He was amenable to it. This would, in my opinion, would be a good use of time considering it'd open up a single part of the engine to the community for modification and thus act as a work multiplier.
Unfortunately implementation would take time, which of course, is in short supply with a one man crew.
As to inventory systems, etc - at least we can say a lot of that is available on the store. Which for me, is a huge boon. However CORE elements of the game engine should have some priority; things which cannot be coded in lua or as a plugin (such as 64bit support). That's my two cents at least.
As to level design; there's a lot you can do with the stock/base/free assets if you try.
There's not a single pay model in this scene. My only complaint is how bright that blood turned out, but that's easily tuneable. There's some base models, Voodoo's free interior bunker set, and some X10 models. Point being, it doesn't look like ****. You have to take the time to put together a game and do it properly. And you need some direction on how to do that (hence my tutorial series) . That applies to ANY game engine, not just GG. Here's some 'winners' from other engines:
Unreal engine 4
One of the most powerful engines out there, clearly a winner in the current market ...
Acknex 8, Aka Gamestudio
A powerful engine if you pay the $$ and put in the time produced this unmitigated disaster:
Unity
Unity is a common choice for game developers these days. Not cheap, but not awful if time is invested.
http://www.pcgamer.com/air-control-may-be-the-worst-game-on-steam/
You have to read it to believe it, but that is a pretty painful game.
On and on it goes.
Game-guru, if nothing else, provides a *DECENT* level of base quality control. Things you know you'll see in a "bad" title:
Rounded terrain, looking very blobbish
Stock assets (of course, why not)
Bad lighting
Simple gameplay (shoot, kill, repeat)
AI that just stands there.
Still, all told, it doesn't do half bad for what it tries to accomplish - provide the tools to make a game quickly for beginners while at the same time allowing really good scenes to get made/games to be created.
The downside is indy games consume a lot of life cycles to make.
Just ask this guy:
http://www.moddb.com/games/my-little-apocalypse-world
He's spent years making one of the best titles we'll probably see on the Game-Guru engine. But look at the results! It's a great looking game. So yeah, kind of rambling here. I think my point is made though.