Here's everything that was added:

**King Slime Boss Fight (Level 1):**
- Giant King Slime with 20 HP, golden crown, boss HP bar at bottom of screen
- 2 phases: Phase 1 (green, slow) → Phase 2 at 50% HP (red, faster, more frequent slams)
- Ground slam attack that shakes the camera and deals 2 damage
- Boss arena at the end of the forest level with warning markers
- Defeating it awards 1000 points and unlocks everything

**Desert Ruins (Level 2):**
- New desert background with sandy ground and golden platform tiles
- Arabian-themed background music
- 3 new desert enemies:
  - **Scorpion** - Fast patrol, 2 HP, 2 damage
  - **Mummy** - Slow chaser, 4 HP, high threat
  - **Sand Worm** - Burrows underground and pops up near the player, 3 HP, 3 damage
- Jewel goal at the end of the desert

**3 New Unlockable Characters:**
- **Samurai** (red) - BLADE WAVE ranged energy slash, 4 HP, balanced stats
- **Druid** (green) - VINE WHIP projectile + heals 1 HP on every kill, 4 HP
- **Berserker** (orange) - AXE THROW (arcing projectile) + RAGE mode (bonus damage at low HP), 6 HP tank

All 3 are locked on the character select screen until you defeat the King Slime. After winning, a Level Select screen lets you replay Level 1 or continue to the Desert.

**Next Ideas:**
1. **Desert Boss** - Add a Pharaoh boss at the end of Level 2 with projectile attacks and summoning mummy minions
2. **Combo System** - Chain kills together for score multipliers and flashy visual effects

**Ready to level up your game? Pick one and let's build it!**