Nayon has just released v-2 of his Metriod: Planets mod for Super Tux. This game, although sitting at version -2, is shaping up very nicely, and is now compatible with firmware 2.0. Here is what is done so far:

Title screen
Samus and environment
Spaceship
X-virus obtaining
Bullets act like metroid bullets instead of SuperTux bullets
Enemies don't disappear when they go offscreen
The screen can scroll both ways - almost done
Samus is always in a mode where she can shoot
Story - almost done
Still to do:

Music - Turns out Machina is doing this, great
Enemy sprites
Upgrades - seems far right now
Custom levels
Free transformation between morph ball and standing samus
Bombs