Greed Mode changes much of the core elements of the game, requiring you to buy everything you need (health, keys, items, etc), and starting you off in a single, large base-room with a button in the center. Off of this room branches a silver treasure room which will always be open and never require a key, a gold treasure room, which always requires a key, a large shop, and a curse room. The second to last floor will not have any treasure rooms, and the final floor will be two separate boss rooms.
Greed Mode has 3 phases, two of which are required to proceed down a floor.
Phase 1 - Waves 1 to 8
The first requires you to fight off a wave-system of enemies, giving you between 5-10 seconds between each wave, depending on the amount of enemies spawned. You reap 18 - 20 coins from this. Completing waves causes charge activable items to increase by one charge. Certain items may charge while the timer progresses like the Glass Cannon. This phase has 8 waves.
Note- You can pause any waves of enemies, but at the cost of health. Enemies won't drop hearts, however rocks and fires are still able to drop from their respective item pool.
Phase 2 - Waves 9 to 10
The second phase requires you to fight two bosses, with 30 seconds between the first and second wave. The bosses are always based off of the floor you are in. Ex: Basement- Monstro, The Shop- Greed, etc. After completing this, the 'exit' is unlocked and you may go down another floor. You reap about 10 coins from this. This phase has 2 waves, with one or two bosses each wave.
Note- You may pause before the second boss as well to use the store.
Phase 3 - Wave 11
The third phase is completely optional, and has you fight a third boss, not in waves. This sometimes spawns two of a boss, or three in later floors. Completing the third phase opens up an Angel Room / Devil Room, but drops no coins.
The Last Two Floors
The Second to Last Floor (The Shop)
This floor resembles a shop, and does not contain treasure rooms; making keys useless. Devil and Angel rooms may still spawn, in place of the treasure room.
The three phases are still required to proceed.
The Last Floor (Ultra Greed)
The last floor contains three rooms. The first room is empty and has a boss door. When entering it, the boss is likely to spawn as Monstro, or some Greeds, but is technically random. Defeating the first boss will spawn 1-3 red hearts. The third room resembles a shop, and is where you fight Ultra Greed.
After defeating the final boss, a "Greed Counter" will spawn that allows you to deposit some of your remaining coins for unknown purposes, as well as a chest to proceed to the credit screen. (The counter will get stuck like the donation counter, depending of the percentage that appears once you defeat Ultra Greed. This percentage depends of the coins that you have donated before with that character).
Ultra Greed Tips
Ultra Greed tends to spawn coins resembling Keys, Bombs, and Hearts and will activate after a short time period. Key coins will open surrounding boss doors, spawning in many shop keepers to attack you. Bomb coins will explode. Heart coins will heal Ultra Greed by a small percentage. It is important to destroy Key coins and Bomb coins as soon as possible, while the effects of Heart coins don't have too much of an impact.
Most of Ultra Greed's attacks are easy to avoid if you attack from a distance.
- Using items with effects that stay until leaving the room can have extreme effects if the user stays from beginning to end, like the Box of Friends of Lilith, Monster Manuel, The Pinking Shears, etc.
- Since enemies will continue to spawn in waves, items that clear the screen can be especially helpful if you are able to let most of the waves spawn (like The Necronomicon).
- Use caution when entering the exit room, as enemies have about a 50% chance of spawning there.
- Take advantage of key sales as items carry over to the next floor allowing you to unlock the next treasure room for cheaper.
- Greed mode is an easy way to unlock Cain as you earn enough coins by the completion of the second floor.
- When fighting the final boss, make sure to destroy as many coins as you can; even though damaging the boss is tempting, you will be reducing the possibility of taking damage.
- The boss before Ultra Greed normally drops 1-3 red hearts and is the only enemy to drop hearts.
- If you can get the IV Bag and any item which drops money upon damage (ie, Piggy Bank), you can likely break the game by basically getting 4 coins for a heart's worth of damage and then buying one for 3.
- Dad's key cannot open the exit door, nor the boss doors featured in Ultra Greed boss-room, despite it's technical ability.
- Despite his massive size, Ultra Greed is affected by tear knock back.
- After being defeated, Ultra Greed puts his hands on his face and is permanently turned into gold until the player leaves, similar to king Midas who had the golden touch.