15
[Prime/GOG] Colt Canyon, top-down pixel-art roguelike shooter
(gaming.amazon.com)
It's showing as $15 for me on GOG.
You need Amazon prime, then go to their gaming site and get the code to redeem this on GOG.
It's not really a "free video game giveaway" if you need to pay for a membership to get it.
This is a place to post limited-time giveaways of full video games that are then yours to keep forever at no cost.
See the sticky post for full details of what to post, how to post it, and other useful resources.
Keep it civil and keep it chill!