The game isn't that hard to understand but a simple tutorial would make it 10x easier to get into. Something that explains the layout when you first boot the game would suffice.
There should be a give up button from the start because I accidentaly had the game running in the background which made my first run take much longer.
You can't increase difficulty so after a few runs the game gets repetitive and gaining
bp points takes ages. Immunity chance is also useless because of this.
Otherwise a good game, keep it up.