Here is the full list of all 19 BrambleLash achievements.
Complete spring in adventure mode
Complete autumn in adventure mode
Complete winter in adventure mode
Defeat 5000 slimeys total
Collect 340 sprites in spring adventure
Complete autumn adventure in 400 seconds
Complete winter adventure without dying
Draw an adventure level with another player (2 - 4 Player)
Complete 6 rounds of adventure mode
Hit 6 enemies with one bomb powerup
Knockout another player with a re-tether powerup (2 - 4 Player)
Burst a shield powerup on another player, then knock them out while stunned (2 - 4 Player)
Deflect a slime king bullet into another player (2 - 4 Player)
Run into a slime trail while affected by the speed powerup
Get hit by your own seed turret powerup
Have 4 players be stunned simultaneously (4 Player)
Draw a battle match (3 - 4 Player)
Win a battle match from 2 points down (2 - 4 Player)
Play 50 rounds of battle (2 - 4 Player)