New version is up. Changes:

The third enemy has been implemented - The Sleeper (as suggested by @PirovanoMichele ). While normally idling, if you get too close, the Sleeper will quickly rush towards you. Keep your distance!
New difficulty curve - enemies now spawn in waves, giving you time to react as they appear on the field. Less instagib right off the bat.

Coming up next:

Local Highscores - easier way to check how well you’ve done.
A few visual improvements - more particles!