They started with the war across the worlds game engine, which is used for all these titles they rapidly release, all have the same basic feel, changing largely the content. I have tried many of them and wasn’t for me, hard to explain as the game engine just doesn’t resonate with me, just feels clunky and dry to me even though looks pretty. Also, does seem like they continue to pop out new releases quickly, giving the impression support and focus moves on. Have even seen posts from the developer where that is purposeful because they need new sales to survive. It will be interesting to see what you all think, but in places I have seen them discussed, seems like a decent portion says the same.
Not sure if they still do it, but if you used to buy from their site directly, you got a steam key right away that gave you access to current version as developed, plus a discount. I did this many times. I do see this for sale on their site.
Although most have positive reviews, just make sure to look how many reviews were even submitted, plus browse through the forums. They do go on sale often after release as well.