Summary:

Welcome to the boundary war, hoards of geometric enemies are out to destroy you. Dodge, shoot, fight back and destroy your foes in search of top scores

There is one catch, the walls are closing in on you. Your bullets will help keep boundary at bay, but be wary, for when shot the opposite wall shall push back.

Submission for Out of the Box:

Theme "Out of Bounds": You are trapped in an ever shrinking boundary, even if you don't go out of bounds the 'bounds' will come to you.

CC0 sound effects from Freesound.org

Music from freepd.com and OpenGameArt.org