Custom Boss Battle Level by Bluefinch, 2018-2019

	
In this short document, I am going to do two things:
1) Explain what goes into making a hammer bros level.
2) Explain how to make a custom boss battle room from an unused level using that information about Hammer Bros levels.


A) Pre-Considerations:
1) This cannot be used in tandem with my pipe-trickery discovery which allows you to teleport to other places on the map.
(see this document for more details on that concept: http://www.romhacking.net/documents/788)
This level will terminate using the treasure chest, so it doesn't regard any special information about where to spit you out onto the overworld map.

2) This should not be used on levels which are more than 1 screen long (F length, which is 16 tiles)
Why? 
The treasure chest might appear in all kinds of inconvenient (unreachable) places. 
It also should not be used on levels which have walls to the left or right.

3) Reason number 2 is a hard caution; if you play-test enough, you'll see all the possible spawn-points for the chest. 
Maybe it can be safe for a longer-than-16-tile level.

4) PROCEED WITH CAUTION: I have a suspicion that this might be compatible with 'autoscroll' (enemy object '211')
because at the end of the level (after it has scrolled completely), the screen is fixed to that last 16 tiles. 
Be careful that the player cannot kill all the enemies before the camera stops panning, otherwise
the chest might appear outside of viewing and reaching range. 
Someone let me know if you have success with this. If you do, then you have made a long boss-battle level. great!



B) That's a lot of considerations and caveats... what good is this again? How can this add value to my hack?
1) It's a good "Next Area" for your level, to provide a boss battle to exit level.
2) It's a good way to use the "Hammer Bros" concept without having them on your overworld map. (this can be problematic in rom-hacks sometimes, for some reason)
3) It's a good way to make a harder boss battle than what stock Hammer Bros provides
as you don't have to just use 1 or 2 enemies, but can add a few more (increasing the difficulty substantially).
4) It's a good way to slip a bonus item to your players at the end of the level, instead of doing it some other way.
5) It is a good change of pace, and just adds some character to the rom-hack overall (in my opinion).



C) So what exactly am I doing?
You're taking a stock unused level and transforming it into a Hammer Bros level.
How? 
By changing some info in the Header and adding a couple of enemy objects. 
The result is that whenever all the enemies on the screen are dead, the treasure
chest appears and you can exit from there. 



D) Here's How!
1) Open up an unused level in your romhack. (Make sure it has enough stock enemies for your desired boss battle.)
2) Open the Level Header Editor for this level, and change the Next Area to this...
3)  Pointer for next area of level — Objects: 20010 or 10010	Enemies: 10
3b) Go to Miscellaneous and change the level length to "F". (See section A for reasoning)
4) Close the Level Header Editor.
5)  Place your enemies and build your little boss battle room.
5b) ADVICE: make this room worth your extra efforts — get creative!)
6) Place the 2 enemy objects which will summon the Treasure Chest, and fill it (see section E).
NOTE: IN THIS CASE, DO NOT include the Treasure Chest enemy object (#82), as it will appear on its own once all the enemies have been killed.
	

E) Treasure Chest:
Object	Description
#186 	Exit level upon getting Treasure Chest
#214 	Type of item to be placed in Treasure Chest (Y position determines item; see below for items)

0 = Nothing
1 = Mushroom
2 = Fire Flower
3 = Leaf
4 = Frog Suit
5 = Tanuki Suit
6 = Hammer Bros. Suit
7 = Jugem's Cloud
8 = P-Wing
9 = Starman
10 ($A) = Anchor
11 ($B) = Hammer
12 ($C) = Whistle
13 ($D) = Music Box