Underpassage

[tukkek]

It would be interesting to have an underground layer to the World acting as a sort of alternative method of locomotion. It would be generated as a series of narrow corridors and some number of entrances leading up the upper world (2 to 5 per World).

With a random chance of once per week, a new Undergound encounter of any level would be added somewhere on the map, effectively "cutting off" that route until the player is strong enough to clear the path once again.

[tukkek]

May supersede #63.

Probably easier to implement once #91 is done.

78 need to be taken into consideration.

[tukkek]

How to handle random encounters here? If they're the same as in the overworld, players might as well just walk straight to their destination instead.

If there are no encounters at all, it becomes less of a strategic option and just a tedious must-take path. The static encounters become a mere yes-no consideration (if an static encounter exists and is too strong, don't use underground).

Maybe just have more #78 hazards (or less but graver ones) and have one of these hazards be a random encounter instead.

[tukkek]

Examples of games that work in a similar fashion:

• Desktop Dungeons uses static monsters and chokepoints to prevent mobility on a small but highly strategic map http://gameshelf.jmac.org/2011/02/09/dd-demo.png
• Shandalar (Micropose's MtG) dungeons work in a similar way, with constant branching and monsters blocking your path https://lparchive.org/Magic-The-Gathering/Update%209/img-4.jpg
• Mario World 3 overworld maps (if not visually, at least gameplay- and layout-wise) http://www.nesmaps.com/maps/SuperMarioBrothers3/SuperMarioBrothers3Overworld.html

[tukkek]

Maze-style map generation would work well for this, as long as the exits align with their overworld counterparts http://www.roguebasin.com/index.php?title=Simple_maze

This also looks like a good algorithm http://arcade.academy/examples/maze_recursive.html

[tukkek]

It's OK to have undergound dungeons as well, further representing the fact that this is a complex network of tunnels fully independent from the surface.

It'd be good if there is a sort of intelligent progression, where the open areas at first have lower level dungeons while areas that need to be cleared through static encounters progressively offer more difficult challenges. A "flood" search from the entry point of the Underworld, combined with narrow corridors, should be an easy way to make this happen: during feature generation, label each tile from 0 to X; then normalize all values to some ceiling-value (20, for example). After that, each have a chance per-tile of having a feature there, or have a fixed or semi-fixed number of features to be placed and scale them according to the tile they land on.