Some gameplay tuning and tweaks for Holdout that I thought would make it a more fun and less of a slog mode to play

Here's the changes:
Total expected session time: 15-16 minutes (vanilla is about half an hour)
Base difficulty: Death Wish (instead of Overkill)
Assault sustain length: 1 minute (down from 2 minutes)
Shorter breaks (from 25 to 10 seconds)
Shorter anticipation (from 15 to 10 seconds)
Damage multiplier caps out at 2 at wave 8
Health multiplier caps out at 1.5 at wave 4 (effectively old one down health)
Excluded Medicdozers from the health multiplier
Excluded Shields from the damage multiplier (they deal a flat 70 damage at all ranges with no falloff in vanilla DW)
Wave modifiers:
Wave 1: Health and damage scaling (starts out at 1x though)
Wave 4: Medicdozers
Wave 5: Only Heavies (doesn't work on San Martin Holdout, Federales have broken scaling in vanilla anyway)
Wave 6: No Stagger Anims
Wave 8: Shields Reflect Projectiles

I was going for something like "short but intense", had more fun playing it myself
I also wanted some more modifiers but I was doing it wrong and it kept crashing and even though it's very easily fixed I was just done with it at that point

also includes borrowed code from Dr Newbie's "Change Holdout Difficulty" to set it to Death Wish. Thanks Dr Newbie!