Pro tip: While holding your ground at the balloon you can hit down every time you must reload. It's not much, but it will build a little while you have to wait for the reload.
Infinite ammo machine gun: When you get the infinite ammo boost from a soulette you just rapidly alternate pressing the slide and shoot keys. This effectively gives you a machine gun!
The "Kitten Smitten Badge" should definitely be an impossible badge for the amount of effort and patience it takes to endure the unresponsive keys, lag, and need to refresh.
I noticed that if you accidentally click on the "end run" button in the background of the shop/inventory/skills menus it will still kill you. I had a really good run that only ended because I accidentally clicked the button.
 "Transmission"){kind=icon}
 "Balloon in a Wasteland"){kind=icon}
 "Rogue Soul 2"){kind=icon}
 "StrikeForce Kitty"){kind=icon}
 "undefeated spider"){kind=icon}
 "Frozen Islands"){kind=icon}
Wow, nice pro tips there