Playing a bit of Tower of Druaga, in the Namco Museum collection. Splatterhouse is in there too, and it makes a good comparison, because you know how Splatterhouse's only draw is the hyper-detailed violence? Druaga is like that except the only draw is the hyper-obscure secrets.
But the secrets made it a huge hit in Japan in 1984. This is supposedly the game that created the Japanese arcade culture of players sharing notes, because the only path to success was approaching the game as a community.
Tower of Druaga clearly draws inspiration from Pac-Man (it's a maze chase) and Rogue (the maze isn't randomized, but everything *in it* is, plus you bump into enemies to attack them) and Wizardry/D&D (theming and upgrades).
To advance past each floor, you need to find the key and the exit, dodging monsters. You can also find a secret item on each floor. These "optional" items are crucial, some are literally required to proceed, and the processes you need to guess at to unlock them are *ridiculous*.
A sampling:
- Kill 3 slimes.
- Touch the left and right dungeon walls.
- Don't touch the outside walls for 12 seconds.
- Swing your sword while standing on the exit.
- Press 1P start.
- Kill 6 colored slimes in a specific order.
- Step on 3 unmarked tiles in a specific order.