Here is the full list of all 30 RiffTrax: The Game achievements.
Finish a game with the maximum number of rounds.
Play a game with the Bad Word Filter on.
Submit a riff using a non-English text to speech language.
Win a round with a riff that is at least 90 characters long.
Play five games
Win a game with double the points of second place.
Receive all of the votes in a round.
Receive no votes for an entire game.
Win a round with a one word answer.
Submit a riff in Write-a-Riff mode that's only sound effects.
Complete a game in Write-a-Riff mode.
Use the "Riff For Me" option in every round of Write-a-Riff mode.
Submit a riff at the last second.
Receive no votes in a round.
Vote for the Riff Bot's riff.
Use a sound effect in your riff in Write-a-Riff mode.
Write your first riff in Write-a-Riff mode.
Win every round of a game!
Complete a game in Pick-a-Riff mode.
Submit a riff within 5 seconds.
Win three games in a row.
Multiple players enter the same riff in a round.
Win more than one round of a game using the same riff.
Use "Get New Riffs" within a Pick-a-Riff game.
Win a game after being in last place at the start of the final round.
Play ten games
The Riff Bot wins a game.
Play two games in a row with the same players
Play five games in a row with the same players.