
Instead of our protagonist Metroid being half Samus, half fish*, she is now part energizer bunny... and still can't crawl.
Jokes aside, this mod does basically 2 things:
1. revamp the health system
- energy number display is % of total life (99 for full) instead of remainder of e-tanks
- changed starting health from 99 to 300, capped max health at 700 instead of 1499
- suits provide no damage reduction
- on default difficulty direct enemy damage is either 100, 200 or 300 now [old 1-69 => 100, 70-119 => 200, 120+ => 300]
Apart from environmental damage health is essentially more like classic platformer where you have 3-5 health dots and enemies do 1-2 damage.
On easy difficulty enemy damage is halved, on hard increased by 50% - there's now a death counter (and quick respawning) for a reason.
2. add a few additional items

Blast Bomb
*bombs and power bombs can remove crumble blocks temporarily and trigger powerup pickups (power bomb in a radius of roughly 3 blocks)
Boost Ball
*enable running/speedbooster in morph ball form
*morph form reaches max speed faster than regular speedbooster
*press up+forward+run during boost to stand up with blue suit active for a moment, then down again to store the actual shinespark
Chain Spark
*hold jump after colliding with wall from shinesparking to regain charge
*regained charge lasts 120 frames in contrast to the initial 180 from sitting down
Detonator
*bombs and power bombs can be detonated earlier than normal by pressing ItemCancel
Drain Beam
*killing enemies slightly refills reserve tanks (max 3/+3 restored per kill)
Focus Charger
*while kneeling, hold up (default L+R) and charge the beam to slowly restore health and missile ammo
*health restore is limited to ~50%
Hyper Mode
*set reserve tank to manual to activate
*beam shots are auto charged and consume 20 energy from reserve
Ice Missiles
*regular missiles gain ice beam like freeze effect
*increases base damage of regular missiles from 85 to 100
Oxygen Module
*allows breathing in liquids
*prevents taking extra damage when submerged in water or lava
Paradox Beam
*can equip Spazer and Plasma Beams simultaneously
*the combinations no longer produce bugged beams, the spazer-less counterpart is used but with +50% damage
Rapid Launcher
*cuts cooldown of all beams, missiles and bombs in half
Weapon Tank
*increase damage of missiles and bombs by 12.5% damage each (max 12/+150%)
Just as a heads up, the overworld is mostly intact minus a few item relocations.
So finding all 105 items should be not too hard.
And I doubt humanity wants to know what a kaizo version would be like.
*seriously girl, how long can you breath underwater or in acid?