- All non-enemy projectiles/attacks seek enemies to some degree and orbiting thorns slowly rotate towards nearby enemies
- Increase size of projectiles/thorns
- Increase speed of stick movement
- Slow down enemies near seed
- Getting hit removes N crystals before affecting health
- Enemies cannot hurt you, but if you fall into a hole you die. Optionally, also add a rising "flood" or timer which will kill you.
- Fill all holes, but any other damage kills you. Same option as above.
- More crystals on the ground and more enemies
- Plant for free but you lose access to all four basic seeds.
- Slightly decrease the size of all holes