Hidden achievement: Complete any 20 waves without selling a single tower. This grants a one-time reward of 500 Gems. Most players accidentally sell early towers to upgrade placements—don't do it.
: The premium currency used to unlock powerful legendary items and permanent upgrades. grim defender codes
Players share these to earn gold. You can enter another player's code, and they can enter yours to benefit both accounts. Community-shared codes from Hidden achievement: Complete any 20 waves without selling
: Participate in the seasonal leaderboards to earn placement rewards. grim defender codes
If you are looking for more than just codes, players often use specific strategies to farm premium currency: