I have added a gameplay video for Story Mode, to give you an idea of what you're getting into! Currently there are four modes available: Story Mode, Survival, Two-Player Local and Player vs AI Battle. I added a new Gag to story mode for the next release which can be seen in here -- the plan is to add new Gags as they occur to me and I have the inspiration to plug it in. We'll see how long I can stretch this joke!
As far as new modes, I'll be adding AI vs AI soon, and you can try to guess the outcome!