Simply amazing, the gameplay is really spectacular. I made a strategy that helped me a lot and could help the others:
Upgrades in priority order:
1- Sword
2- Potion
3- Extraction Power/Speed Bonus (Both increase your speed in different ways)
4- Armor
5- Boots
6- Rocket
7- Oil
8- Luck
Now that "Faster than light speed" will be a hard medal to get, but as I say: Challenge Accepted. xD