Amazing job on this! A short game, but it was very fun. However, the game is not without it's flaws.
-Tier 5 Cooling System needed in order to go a little over 1/4 depth past the second rock layer
- Didn't notice a difference between different drill heads, aside from faster digging and a recolor
- The game just abruptly ends. It's like "Oh yeah, you got the source of infinite power. Well bye."
- Generosity with money. After you get all of the best equipment, you still get an absurd amount of money that you can't do anything with.
All in all, the game was very enjoyable, aside from the drawbacks I listed. Keep up the great work!