Here is the full list of all 30 Rocket Fist achievements.
Complete Sector 1
Complete the Tutorial
Kill 3 players on multiplayer with one single punch.
Parry an enemy fist with your own fist 20 times.
50 bounceshots.
Destroy 10 cannons with its own bomb.
Destroy 25 enemies with bombs.
Block 10 incoming fists with the shield powerup on multiplayer
Win a deathmatch against three opponents without dying once (invincible title)
Complete 5 multiplayer matches without destroying any robot (pacifist title)
Smash at least 2 robots with one dash while using the Big power up on multiplayer
Destroy 15 enemies while using the Shrink power up on multiplayer.
Beat a non-tutorial sector without dying. (Normal difficulty or higher)
In a Survival match, have the highest number of kills and still lose the match.
Have 30 Double Kills
Have 50 Stunsteals
Stun the same enemy 10 times.
Destroy a bomb robot and die within the explosion.
Set the music volume to 0.
Catch 20 incoming fists.
Complete Sector 2
Complete Sector 3
Complete Sector 4
Complete Sector 5
Have 10 Close calls, with only one life left.
Play 50 Deathmatches
Play 50 Survival matches
Have 25 Indirect Kills
Hit 3 Longshots in the same multiplayer match
Get an after death kill.