Researching different artifacts could bring small permanent bonuses: food bowl gives an increase to food nutritional value, laser pointer makes suit hold more charge, fish bowl more air (;)), toy mouse or cat tree increase movement speed. Possibly only when researched for the first time - duplicates do nothing. Might need to rebalance and lower base kitty stats a bit to avoid making cats TOO AWESOME.
More vehicle types:
- Dirtbike: fast, turns easily, no trailer attachment, low HP,
- Bulldozer: crushes trees and rocks to raw materials, a ton of HP, very slow. Mostly for clearing area out for a new base.
Glider: no HP value, flies over obstacles. Might have a solar recharging station?
Mining: drills, wells (VERY slowly filled with water, shows [!] to pull out a bucket + an upgrade which automatically puts water into base supply), geothermal heat pumps, cave systems...
A crazy sci-fi branch of tech tree:
- Teleporter base module,
- Food replicator: takes chemistry, makes
Earl Grayslop, - Ray gun: blasts rocks and trees instantly, requires ATOMIC FUEL every dozen of shots or so,
- Base AI module: doesn't do much, just quips,
- Anti-gravity generator: for building no-wheel-barrows (like trailer, but follow behind the player).
In short: cool stuff, not always practical.
Trains! As in, an entire rail yard. Narrow gauge for mid-game, with locomotive built on bio-fuel generator (eats greens to run). Say, a sheet of metal and a piece of wood could make 3 pieces of straight tracks, 2 curved ones, or one specialty (switch). Maybe also mine carts and handcars (require pushing keys to run)?
With more advanced tech: monorail or mag-lev. Tracks made with metal bars and stone (hopefully not electronics, as these are very expensive). Locomotive requires 2-4 RTGs to be built, but no fuel afterwards. Building rails would be a nice late game money sink :)
Some use for tree seeds ;)