update roadmap with absolute minimum

docs/roadmap.md

@@ -4,10 +4,19 @@
 - [ ] Vehicles
 - [ ] Swimming (inkl. Oxygen-Meter)
 - [ ] Global Progress Object
+- [ ] Menus & Textboxes
+- [ ] Save & Load
 - [ ] Mobile Controls
 - [ ] Spores
+- [ ] Webhosting
 - [ ] Boss Battles
 
+## Absolute Minimum to Finished
+
+- Swimming with depleting oxygen
+- 1 vehicle
+- Winning condition
+
 ## Biomes & Levelsetups
 
 - above sealevel