Just did a playthrough of the august demo and I love the improvements over the june one. Making movement acceleration faster and adding mouse sensitivity were the 2 things I really wanted. Maybe add an fps cap option next since I don't think everyone wants to run it at 300 (I cap mine at 60 with nvidia).
The issues I ran into were cheeks rockets seem to collide with themselves or the terrain under them so they explode right as they fire. The new pathing that lets enemies fall off ledges for ambushes makes them fall to their deaths in the first level's "reactor" room. You can get stuck by jumping behind the two yellow pipes near the end of the first level.
Keep up the good work. This game is an instant classic in my book and I can't wait for it to sit in my steam library.