I can quickly go though the ones I’ve toyed with in order from easiest to learn to the hardest IMO.
Twine - Pro: Free and easy to make simple choose your own adventure stories with some room to explore more advanced stuff with HTML, CSS and Javascript. Con: The games you make are would be as interactive as a website, which still leaves you with a lot of choices when it comes to game genres, but you’re not going to be seeing many Beat 'em ups or Rail Shooters in the engine. Also the latest version of Harlowe does not support making your own functions and macros. Also, also, because these games come out in HTML files, it is remarkably easy for users to hack into the game and mess with the code or steal assets. Best Examples: Abducted: a WGHFY story, Insatiable Hearts Recommended for: It’s primarily meant for “Choose Your Own Adventure” style games, but I’ve seen really good Visual Novels, Turn Based RPGs, and Management Sims made in this engine. A good choice if you want to focus on your writing skills.
Quest Text Adventures - Pros: Free and easy to learn Cons: Minimal text based interaction with very little support for audio/visual elements. Can sometimes feel really janky on the player’s side. Some games require the player to register to the Quest website to save and download games. Best Examples: Leotard Leslie in the Land of the Luscious Ladies Recommended for: Someone who wants to remake thy Dungeonman for some reason.
RPG Maker - Pros: A classic choice with lots of userbase support. As interactive as a game you can make without having to code collision detection. Also comes with plenty of art and sound assets to use in your games. Cons: Expensive as hell, I was able to RPGMaker MV on the Humble Bundle a few years back, but there’s no telling when the next time it’ll come on sale for a reasonable price. Also there are a bunch of features that start to become constricting once you learn how to be a better game designer. The best games I’ve found on this engine basically have to break the engine in order to make the game work, which at that point, you might be better off using something else on this list. And while there is the option of greater encryption than twine, it is still easy for hackers to steal assets. Best Examples: Super Fatty RPG, Apostles, Draconic Expansion Recommended for: Creators who want to make an interactive game without having to work hard at programming or sound effects or making art assets. Also, JRPGs (Obviously)
Ren’Py - Pros: Free, easy to code and make a game with as many or as little art assets as you want. Supports still pictures, simple sprite animations and playing prerendered videos during gameplay. Cons: It’s a visual novel engine, that said I have seen some creators make some interesting minigames out of it. And like Twine and RPG Maker, it is somewhat easy for hackers to edit the code and steal assets. Best Examples: The Weighting Game, Fill Me Up, Feed My Affection Recommended For: Same as Twine except with a focus on Art and Visuals over Writing and Text descriptions.
Gamemaker Studio - Pros: Fre- wait, what? Cons: $5 a month? Oh, fuck off! Best Examples: A lot of good old games from previous jams… sigh… Recommended for: No, no! You don’t want this. You want the guy in the next paragraph.
Godot - Pros: The New Hotness, Free, Supports multiple programming languages, regarded as the best engine right now for making fast paced 2d games. Cons: You need to know actual computer programming and game design in order to use this. Best Examples: Honey Combat, SWEET (No Public Release at this time), A bunch of other games that I can’t seem to find right now due to a lack of tags. Recommended for: Wheel Game Devs, especially those who have been soured by GameMaker Studio going to a subscription based business model.
Unity - Pros: The Old and Reliable, Free*, Used by professional game studios and so has major user-based support. Cons: User Interface is part of the game process which can result in weird glitches, poor support for 2D graphics. Best Examples: Chub, Chomp, Chill, Helltaker (and therefore Fattaker) Recommended for: Folks who might end up working for a major studio someday, or who hate Godot for whatever reason.
*At the time of this writing, Unity is free for individuals and companies who make less than $100,000 per year in revenue from products that use their software, but require a subscription to one of their business plans when the revenue exceeds this cap.