Here is the full list of all 17 EleMetals: Death Metal Death Match! achievements.
Complete the tutorial
Complete the credits
Win a round without getting a kill
Win a round without throwing a shard
Make it to the final area on a scrolling level
Get 8 or more kills in a single match
Finish a full game with more than 30 kills
Play 100 matches
Kill an opponent with a revive explosion
Revive 4 times in a single match
Witness the big bang when two charged super attacks collide
Hit 2 or more opponents with a single charged super attack
Bounce a charged super attack off a ricochet platform
Kill an opponent by deflecting their own shard back at them
Deflect a single shard 10 times
Headbang with 4 players at the same time
Have 4 souls simultaneously active