Pretty cool and short game! My only issue (or a nitpick) is that there isn't so much to be done here. Maybe if the player had the ability to jump over spikes or something (or change floor levels) to avoid obstacles, this could be interesting resource/time-management game, where you need to constantly keep your speed high enough, so you don't run of time, aim and shoot, so you don't die and also change floors/levels to not run into spikes/vines/trees/anything
Particles and tweens were really good though!