Kartridge is described as 'Introducing a new PC platform by Kongregate, designed to be different. Kartridge, the community-driven, developer centric platform is now in open beta' and is an app in the Gaming Software category. There are more than 10 alternatives to Kartridge for a variety of platforms, including Online / Web-based, Windows, Mac, Linux and Android. The best alternative is Steam, which is free. Other great apps like Kartridge are GOG.com (Free), Humble Bundle (Paid), itch.io (Free, Open Source) and Epic Games Store (Free).
itch.io gives you the ability to design a page where people can download games you have uploaded. You can optionally put a minimum price on your game (which can be 0), giving people the opportunity to pay you what they think you deserve. All files and images are hosted on itch.
The Epic Games store is now open, featuring games from other developers. Epic's goal is to bring you great games, and to give game developers a better deal: they receive 88% of the money you spend, versus only 70% elsewhere.
Legendary is an open-source game launcher that can download and install games from the Epic Games platform on Linux and Windows. It's name as a tongue-in-cheek play on tiers of item rarity in many MMORPGs.
Indie gaming is coming to mobile! With this app, you can easily install Android games from itch.io and keep them updated. This provides an alternative to the Google Play store for indie game developers and enthusiasts.