Neo-geon

Neo-geons are randomly generated dungeons with 99 floors. Once the player enters the dungeon on the 1st floor they must continue from floor to floor through Gates until they either reach an Exit gate, fall in battle, or give up. Consecutive floors are named based on a theme, and these themes determine the tile set, enemies and traps the player will face. Several floors feature a "boss" battle against one or more strong enemies that must be defeated to open the door to the floors' exit gates. Each of these boss floors (except the 99th) have a single treasure chest, and will always have a number of gates (including an Exit gate) to allow the player to choose whether or not to continue deeper into the dungeon.

Random dungeon layout
Random dungeons are created by assembling pre-designed rectangular "blocks" of varying sizes, complete with walls, floors and enemies. Walls around the blocks are removed where they overlap in order to allow the player to get from one block to the next. One block is selected to hold all of the gates, two to three gates are then placed in random locations in that block. Depending on the size of the block, the gates may end up very close to each other.

Once assembled, traps are randomly added to the map. For most themes, traps are usually most dense one to two spaces from the walls of the block, but some themes have more consistent trap placement. Finally, a starting location is selected for the player. Occasionally, the player may end up starting in danger, either placed on an ice fountain or in the path of a fire jet.

Monster Levels
Neo-geons have a "Monster Level" statistic that increases as you pass through gates. With the exception of Doom Floors, the monsters placed on the floor are within a couple of levels of the current Monster Level. Trap damage is also scaled depending on the Monster Level. Items found in treasure chests also improve as the level increases.

Gate Levels
In Neo-geons, each type of gate has a level from 1 to 3. All gates of the same type are the same level, in other words, once an Angel gate changes to Lv. 2, all other Angel gates will be Lv. 2 until it changes again. Changes in gate level are random, and a gate can change from any level to any other level (for instance, from Lv. 3 to Lv. 1) though level skipping is rare.

Warp Gates
Warp gates are only available in Neo-geons, and in addition to increasing Monster Level and item drop and rarity rates, they have a chance of allowing the player to skip floors.

Neo-geon Floor Themes
The Neo-geon floor themes and bosses are also used for the Normal branch of the Tri-geon.