This is "Herogest", a game concept I last worked on back in March of this year. It was my one attempt at something procedurally generated and it didn't get very far before I decided a game much more demanding to make and far more derivative of some other game was the right path to continue on, so I quit this.
The idea of the levels were to seal as many of those enemy spawners as possible to unlock the end boss door. In this video only the "Dullahan" skeleton enemy appears from them. The enemies coming from those would be stronger and harder, and the not-working Succubus that is shown was another of them. You would also collect generated treasures and rescue people.
Last I worked on it it could generate rooms completely, work from a template that it could make changes to, make multiple doorways leading alone the "main" path and also make side-rooms. It could pick at most two out of six "trap" features shown in this video, like the spike wheels or the thunderstorm.
The game was going to have items, very much like Zelda (but the game is far more action-oriented). Paths leading to side rooms and rooms AFTER the mini-boss room could be blocked by obstacles you needed the items for, like water or strong blocks. The bosses would generate parts and features that adapted to the dungeon's chosen theme and item.
Going more beyond what the engine ever had, the game would create a hub world leading to three generated dungeons with something in the center of them, and then you'd play a fourth and final dungeon that always had the same tileset after beating those three.
I seem to stick with the games that are the largest in scope in some stupid way which is probably why I quit on this to resume Iconoclasts! Looking at the game now I feel it could've been really fun and varied.
HOPE YOU LOOK FORWARD TO "THE ICONOCLASTS", THOUGH!! Whenever I finish that undertaking I'm definitely not making ridiculous projects like it anymore.