play from scratch or carry ammunition forward?
It's not obvious whether or not a map is meant to be played from scratch or played with ammunition, health and weapons carried forward from the previous level. However there are some signs you can look for.
Note: "is meant to be" is different from is possible. The only way you can tell if a map is possible to be done from scratch is to actually go and attempt it.
the text file says what to do
Probably the most obvious case. If the text file says how to play a map then that's how the author intended you to play it.
(Of course you are free to ignore him...)
it's an ExM1/MAP01
So naturally you're forced to play it from scratch.
previous level deliberately killed you at the end, but exited anyway
In this case the game respawns you with 100% health and 50 bullets. Usually achieved by killing both you and a Romero head, or killing you but knocking a voodoo doll over an exit line. Scythe does this, for example.
Not the same as dying in an exit damage sector (in which you don't actually die, and start the next level with <10% health but all your weapons and ammunition)
there's a weapon right there at the start to pick up
This is usually a shotgun. Indication that author has likely playtested it from scratch. However in rare cases despite the presence of this weapon you could find yourself out of ammo. Or it might be contradicted by one of the reasons below.
it's a single-map wad that for some reason doesn't replace map01
The usual reason a map is not numbered 1 is it depends on some level-specific effect (map07, ExM8) or the author prefers the original music for that map but doesn't want to rip it out the iwad.
However, it's still a single-map wad. I've never seen a map where the author intends you to bring all the weapons and leftover ammunition from Doom 2 maps 1-6 into the start of his map07 replacement.
more than one consecutive wad in the map
There's always the possibility that when you're in a multi-map wad you're supposed to play through all of them at once. However, the simple case of having more than one map in a wad is, by itself, not enough information to go on.
Some obvious cases where maps are meant to be played from scratch include:
- Community megawads are more like collections of single maps, designed by authors working entirely separately, and should be played as such. These will usually say so in the text file.
- Wads by speedrunners and demorecorders, even otherwise with obvious flow between maps, are primarily meant for each map to be played from scratch, as it is much easier to record demos of single maps.
- More generally if you find that after one or two maps you seem to have full ammunition, health, and all the weapons, you're probably not meant to be carrying it forward. On the other hand it might just mean the maps are really easy and, arguably, overbalanced.
A much clearer indication of carrying-forward intention is where the maps themselves follow on; that is, where the start of the next map is identical to the end of the previous. However I've seen wads where the maps follow on, but also have a shotgun easily available at the start. UAC.WAD was a great example of this. It turned out you could do all the maps from scratch but some were... tricky.
Experience tells me that for most wads the author thinks that while you can play the maps one after the other it's easier to balance each one individually.
The best indication a map is not meant to be done from scratch is that it has large amounts of ammunition you can't use, but could if you had played through a previous level and picked up the right type of gun there.
pile of resources at end of previous map
If there's something like a weapon, megasphere, or large amount of ammunition at the end of the previous map, and it was pretty much unavailable until there were so few monsters left to use it on (or even none) then it's likely you're meant to carry the stuff onto the next map.
At least, if the map was made by the same author, it's not part of a community wad or something, or it's not just the case that the author always puts a soulsphere by the map exit as some kind of signature.
nowhere enough ammunition to beat the map
Bit dubious though, there are lots of reasons why a map might not have enough ammunition. Perhaps infighting is intended. Perhaps the author is too good a player (although this usually means the monster count is higher rather than there being a lack of ammunition)
The reason I started writing this was because I was replaying Wonderful Doom and from pistol starts several of the maps seem to have excessively low ammunition. However others have weapons at the start, although not just right there stuck under your nose.