itch.io

Science-fiction. Commonly including things like aliens, advanced technology, and settings of outer space or distant planets. 

Also known as TTRPG, tabletop role-playing games are tabletop games when you play a character within a set of rules. Typically actions are determined by speech and checked for success via dice rolls.

Unity is a game engine for 2D, 3D, AR and more

Unreal Engine is a 3D game creation tool