My players really enjoyed this. Players also starting eating the demon eyeballs. I came up with an increasing scaled curse for each one eaten. Note, that the 3 of 5 players who have eaten the eyeballs have refused Remove Curse spells to undo the below. I've had a player knock himself unconscious multiple times to this. 1 eyeball - For eating a demon eye, you now add do an extra 1d8 necrotic damage on attack roll of a 20 (aka a crit) and on 1s you do a critical hit to the nearest friendly creature. If attacking with advantage and the lower dice is a 1, the effect still triggers but the higher dice still counts if its good enough to hit (so you could hit the monster and trigger the effect). Works same way for attacks at disadvantage. If the dice that doesn't hit is a 20, you do 1d8 necrotic damage to the monster.
2 eyeballs - If you roll a 20, you add 2d8 of necrotic damage. If you roll a 1, you do a max damage critical hit to the the closest party member if in melee or on a range attack it is a random roll to pick among any party members in range. If for some reason no one is in range for either type of attack, you inflict the damage on yourself. If you are rolling with advantage and roll a 1, it will be an extra attack against a party member or self like above (so it won't take away any hits from the advantage roll) as a max damage critical hit. Same applies to attacks with disadvantage and rolling a 20. You'll do 2d8 necrotic damage to the bad guy as an extra attack. 3 eyeballs - 3rd demon eye, the effects now trigger on 1s & 2s and 19s & 20s. 1s & 2s do max critical damage and 20s do 3d8 necrotic and 19s do 2d8 necrotic. Same rules as above for advantage / disadvantage rolls.

I love the Dungeons on Demand adventures series. They are so easy to fit in to an existing campaign when I need some more time to prepare on other stuff. I understand levels 1-20 are covered at the moment but I would really buy another series of adventures!

I used Eyes on the Prize as a special hidden entrance into a desert fort in the mountains of Anauroch. Just a small detour before a big climactic battle with the blue Wyrmspeaker (we started playing Rise of Tiamat but we went off track really fast, leaving all of the source material behind us).

spoiler alert

The only thing that bugged me about this adventure is the Oculisk. What is an oculisk? I scoured google but couldn't find anything on them.. Otherwise, great adventure! Loved the lineair approach of the dungeon.