Funny stuff I've noticed about the D1 Final Boss

[Xfing]

While tinkering with the files to modify the D1 bosses for D1,5 I've decided to take a look at their in-game behavior to look for inspiration. I was forced to conclude that in many ways this boss' AI routine was more advanced than those of the D2 bosses.

- Even though his normal attack mode is firing 2 megas at a time, he periodically also makes a huge discharge of a random number of Megas at once (on Insane) which isn't triggered by sight - he just does it on a whim, or straight after teleporting. A typical boss behavior pattern from platformers etc. - you need to know when to duck for cover. Well, more than you usually duck with this guy anyway
- Spawning robots all over the room

Both of these things are impossible to replicate in D2 without tinkering with the code, which is pretty sad. But I've also noticed a Parallax goofup - the upper left launcher of the robot never sees use in D1 - instead he launches missiles out of his eye. Probably an intentional easter egg of sorts, haha.

[Alter-Fox]

Spyhunter!
I don't mind if it's a glitch or not since it's impossible to write a perfect computer program as long as you're still any living organism. You just have to make sure all the bugs left are small ones.

As far as I remember from fighting him, you get so many invulns that ducking for cover is pretty irrelevant anyhow. Though I've never got that far on Insane, the farthest I got was Oberon.

[Xfing]

Spyhunter!
I don't mind if it's a glitch or not since it's impossible to write a perfect computer program as long as you're still any living organism. You just have to make sure all the bugs left are small ones.

As far as I remember from fighting him, you get so many invulns that ducking for cover is pretty irrelevant anyhow. Though I've never got that far on Insane, the farthest I got was Oberon.

Being invulnerable is fine and all, but being hit by 8 Megas will definitely disorient you a bit, haha.

[Calmarius]

The descent final boss has behavior is rather interesting indeed.

First the boss has a lair, which includes all cubes one can move from the boss' initial location. The boss spawns robots into these cubes randomly until a certain number is reached, also the boss uses these cubes to teleport to.

So this mean many things: The boss can neither teleport outside the lair nor can spawn robots outside the lair.

When the boss teleports into a cube it doesn't fit to it will take some damage which makes him teleport again right away.
This means in fan-made levels if the author doesn't give enough room for the boss, the boss can actually commit suicide this way.
This is also the reason that in level 27 the boss can only teleport into one of the 4 big cells in the room, it doesn't fit to any other cube.

I also believe if 4 players in co-op mode pick up an invulnerability each and block the boss' location in level 27, the boss will eventually commit suicide - try it!

This teleportation always happens in a way so the boss facing to the player, and it also resets its internal counters so this huge barrage of missiles is the result of the boss teleporting around you in cubes it doesn't fit to, an it fires a missile in that single frame too.