Although Undertow is presented in 2D, Chair's artist team did everything they could to get the most out of the visuals. The only complaint I really have is that everything is so small. While I get that they're small to get the most out of the play field, unless you're using one of the bigger units, it is can be hard to find exactly where you are on the screen, especially when units cluster up around an area and start shooting. The accompanying explosions are beautiful, especially when set against the otherwise murky colors, though they do add to the clutter. Not being able to tell what is going on does, however, give the game a fun sense of suspense while you wait to see if your unit squirts out of the chaos, or is forced to respawn.
The one element I like the most about Undertow's graphics is the feeling of depth in each level. The dark colors keep things from popping off the screen; instead they help create a feeling of depth. This is especially noticeable in later maps where you'll see units darting behind and between ruined temples.
There's music is Undertow, though it isn't very noticeable, especially during gameplay. The only thing you'll hear throughout most of the game are explosions and the tell-tale chime informing you that you're either about to capture a spawn point or lose one. Though I couldn't begin to explain the game's story, there are story sequences inserted between levels. The voicework is okay, though some of the dialogue is unintentionally goofy or just overplayed.