The latest games to be offered for the low price of free to users of the Epic Games Store are Sonic Mania and Horizon Chase Turbo. And while I cannot speak for Horizon Chase Turbo, I can safely say that Sonic Mania is fan-freaking-tastic.
Sonic Mania is a love letter to Sonic games in the Genesis days. It features familiar 2D gameplay that has been brought into the modern era with a few extra bells and whistles. It is an all-new adventure though you will visit some familiar territory. It all ties into the story, so you'll understand what I mean if you decide to play it.
In keeping with the idea of speed, Horizon Chase Turbo is billed as a "tribute to classic arcade racers" of the 80s and 90s. This is pure arcade style racing that leans more towards old-school visuals than modern eye candy. It features 111 tracks and 48 cities to race through. It also includes 33 unlockable cars and 12 different "cups" to try to win. Multiplayer is limited to local 4-player split-screen or an online Ghost Mode against friends' times and a global leaderboard.
Both titles will be available for you to add for free to your EGS account until July 1st.
tl;dr : 31 hours spent in this game, haven't gotten sick of it yet, haven't finished it yet. The pros outweigh the cons in my experience. It's worth it, and since it's free, get it and play the damn thing. I am vouching for Horizon Chase Turbo.
The game slows down if you play for a while (most notable when on courses that take a long time to finish), but the developers are blaming that on an older version of the Unity Engine, so they're going to update Unity at some point of time (stating the pandemic delayed everything). The other downside is rubberbanding AI, where the only threat is the car in first place. Every other car is only there to act as your obstacle, protecting their glorious leader. They also have perfect handling, capable of any turns with maximum speed (something the player can't do on any car), and crashes don't slow them down (I've seen them spin out and keep going without any loss of speed, it looks weird) while crashes punish you severely.
The good side? Every AI car except for the ones in the top three positions are slower than you overall by design, and you have more nitrous than any AI car. And lastly, if you are in first place, then you can relax, because nobody will ever pass you if you don't crash. Tons of modes (completionists will have a lot to do here), no online but you can do remote play with splitscreen, cheap DLC (including one that references Outrun and another that is free, catering to novice players), and a beautiful art style, complete with weather effects and day/night cycles to make races more interesting. And while the cars are fictional, they have tons of parody vehicles referencing Eastern and Western culture (namely memes). Heck, I'm using one for my Endurance run right now (a mode that consists of a marathon involving all 111 courses and I'm currently at 70 - achievement is outdated showing 109 races but there's 2 more added at some point). And the soundtrack is perfect for this game. Barry Leitch (Lotus Turbo Challenge, SNES's Top Gear, Rush) made amazing music that you will enjoy, especially when you startup the title screen (you'll suddenly start thinking of Patrick Phelan).
While I haven't see any content updates, the developers haven't left this game, and update with in-game race events on a weekly basis (Playground mode). So far, I don't see any rewards for completing them, but the upcoming one on June 29th will give you new skins for cars. Supposedly more updates coming according to their recent Steam news post so we'll see what happens.