If you're a fan of the weirdly fantastic indie game RunGunJumpGun, you'll be excited to hear that Amazon is offering a free download of the PC version for a limited time. The only catch is you need to have a Twitch Prime account, which you can access at no extra cost if you already have an Amazon Prime membership. Otherwise there's an option to sign up for a 30-day trial. Developed by ThirtyThree Games, RunGunJumpGun is like Super Mario on steroids, featuring dark colorful worlds and quirky characters. You only have until this Sunday, February 5th, to grab it for free from Twitch Prime so you better move fast.