It's an 'ok' game thing - but definitely not worth a monthly fee.
If it was a $1 to $5 one-time payment that would be ok . . . who pays a monthly fee to play a phone game for 5 minutes a day? The only increase in brain activity you should have dear gamer, is to understand that.
There are a lot of free, fun games out there that are mentally challenging, and some great ones for ONE PAYMEMT of $2.99 or less.
Also - did'ja ever notice how a lot of reviews mention the same negative experience? I see a whole lot of reviews mentioning problems with the payment, & not getting the game, or the game not working properly & little or no tech support. . .
The game asked me to review - and on that review forum I saw many of the same issues mentioned. here by those who embarked on monthly or yearly payments.
Also saw a lot of comments about how boring the repetitive free game is, & the inability to even replay some of those.
I found it weird that I could replay some of the games & improve my final score, even if I missed 1 or 2 more than on a previous score. I think the game does this to falsely build your ego - makes you think you're smarter - if your 'smarter' then by a sort of psychological-innuendo you should be getting bored with the 'easy' free version & be psyched (& apparently hypnotized) to pay not only for the game, but continually pay for it monthly . . .
On that same review forum, after several of the same poor reviews, there was an extreme rash of one word-praise reviews, or no comments, just 5 stars, making it pretty obvious everyone & their cousin affiliated with Lumosity glommed-on to boost ratings.
So herein is wisdom, if you wish to increase your apptitude, heed these warnings so many have shared, and research other interesting, challenging that aren't tryin' to scam ya.