With the wife and boys out of town for a few nights, I took one afternoon to see what I could make in 4 hours. I was really pleased with aspects of the language and libraries that, compared to my language of trade (C/C++), enabled me to add features almost as quickly as I could think of them. A+ would use again, especially if they could figure out mobile platforms.
For mobile, take a look at Moai[1]. I don't like it as much as LÖVE -- it feels more low-level and fiddly to me --but it's Lua and it's pretty full-featured.
I work on Moai - we just shipped 1.0 last week. It's designed to be a minimalist, open source framework for game development. We think that's the best approach for experienced game devs - look at Bungie's Crimson Steam Pirates on iOS and Chrome for an example of what you can achieve. If you need a higher level scene manager, then check out Rapa Nui for Moai at https://github.com/ymobe/rapanui
If you want to write mobile (outdoor) games using Lua, take a look at my site http://geolua.com/
It allows you to write (multiplayer) games that execute in the Browser. Lua is executed on the server side. The browser side is implemented in GWT and is getting pushed the game state.
It really is too bad that they still don't have anything for iOS/Android. I used Love a fair bit a couple of years ago and I seem to recall a few people who had been able to get it working on iOS, it doesn't look like anything came of it though.
Although not suitable for all games, my favorite part about this engine is how well tied in box2d is in Löve. The developers have made it feel almost seamless, which makes the engine a lot of fun to play with. https://love2d.org/wiki/Tutorial:Physics
I discovered LÖVE sometime around this february. We have a Game-making group at university, so I wanted to show them too. All went well until we looked at the libraries :/
Not the parent, but -- in my experience -- many libraries from the community were written by enthusiastic amateur developers. Finding ones I enjoyed using was very needle-in-a-haystack.
Along with that, a lot of the libraries (from what I could tell) put all the code in one massive file in a forum thread and update it from there, making it pretty time-consuming to keep up with changes.
That and there's no consistency between libraries as far as how they decide to use classes.
My solution to this was to not use any of them. The LÖVE APIs are pretty sane, so using your own tiny wrappers is not much work compared to dealing with the libraries.
This has been posted in some form or another a couple times, but, having written a few thing with Löve I absolutely recommend it, especially if you're looking for something to learn Lua but can't think of a project to start with.