The two mystery weekly giveaways turned out to be Sunderfolk SE (Standard Edition) and Telltale Batman SE (Shadows Edition) which is both games with their shadows mode DLCs.

Sunderfolk - Standard Edition Link[store.epicgames.com]
The Telltale Batman Shadows Edition Link[store.epicgames.com]

Details:
- Account/DRM required: Epic Games (NOT Steam)
- Offer good through May 21, 1500 GMT
- Sunderfolk Steam store page for evaluation.
- The Telltale Batman Shadows Edition Steam store page for evaluation.

There are also two developer giveaways for Lost in the Hole[store.epicgames.com] (until 2300 GMT on the 16th) and Devil's Island[store.epicgames.com] (until 1000 GMT on the 16th). These are not official Epic freebies so your quality may vary.

Next week, the Epic MEGA sale will bring us two more mystery games. Hopefully they will be as good as these two.

LH
It's kind of fun having mystery games back. They should just stick with that.