Been playing the game for a few hours now and I thought it was pretty fun and quite addictive, but yes it's not perfect, so here's my feedback.
First of all, the theme itself about brain and depression etc is not very appealing, but maybe could be done appealing if it had some awesome graphics, but still it's a very odd concept. If you remade the game using some more traditional theme's like medieval, demons, zombies, military, that would be more appealing to many as it's part of popular culture. Gameplay is pretty solid, but graphics is and UI needs to be polished. Music and sounds effects are okay.
Gameplay wise, it takes forever to build up enough motivation to be able to pass the first 5 levels. I've been playing the whole morning, replaying the first four levels 20-30 times to get enough motivation. Motivation gain is way too low, and you get quite bored having to repeat levels over and over. I did level 1, maybe 15 times, because it was the fastest way to build up motivation to purchase upgrades. I've been playing 3 hours and still hasn't passed level 6. The game becomes more of a grind than strategic.
I still think it was quite fun though, but the things I don't like is the theme, the graphics, and UI. It just doesn't feel very appealing.
If you used the exact same gameplay levels and everything, and just changed the theme, and with some more polished graphics and UI I think a lot more people would find it interesting.