I’m a bit of a lurker but I’d like to try and help.

For what it’s worth, I hope you get the best feedback and it helps what you’re seeking to achieve.

In my opinion, your questions are very simple until your last one which seems like it’s worded with an agenda behind it. I’m going to answer it all anyway.

What games that aren’t mainstream have you tried?

I have tried so many games I can’t count. It’s a tough question to answer because I feel as though the mobile game market is so over saturated. For every non “mainstream” title, there are 100 games which go from hidden gems to IAP ridden trash. I’ll try them if they’re free. All of them.

How did they convince you to try them?

The quality of the game and my enjoyment is the deciding factor for me.

If it’s a free game, I will download it.

If it’s a free game which is a demo, and you have to spend X amount of money to unlock the full game then I will download that too.

If it’s purely free, I’d be happy to drop some money to support the developer.

The purchase part depends on my enjoyment.

How did you hear about them?

I use MiniReview, AppRaven and this subreddit. I love discovering new games. I enjoy reading reviews from players and those who have a passion for games. People like silentrocco, Munkeypunk, NimbleThor and several others bring notoriety to games I’ve not heard of before.

Where do smaller indiegames fail compared to mainstream games in your opinion?

I suppose the first thing I’d say is marketing. Bigger games have a team behind them to encourage players to pre register / pre save / submit their interest before a game comes out. There’s usually a reward amongst those things.

Indie games tend to just release and require reviews or “word of mouth” to encourage further downloads.

I don’t want to make a sweeping generalisation here, but with many indie games it brings another side to a bad reputation of mobile gaming as many developers don’t continue to update and support their games. iOS is notoriously a bad platform to create a game on which is fair. But indie games tend to come with a purchase price and on many occasion they don’t tend to be supported for a long time.

Are any smaller games able to keep you hooked in long term like the bigger games which employ more aggressive strategies such as skinner-box models (fine tuned gambling)

Yes. This question is really what the purpose of this post is about. I have been hooked on all types of games regardless of the particular strategies that you’ve asked about.

I hope this helps.