I had a lot of fun playing this game! Great job for a first try and I really will look forward to any updates or new games made by you :)
I had a few things I would improve with game, including time it takes to start rounds, the effectiveness of the shotgun, not being able to shoot through your walls etc. I spoke about it a lot in my youtube video.
There were a lot of aspects I enjoyed about this game including the simplicity, the idea is similar to the last stand, but you can actually move about and most importantly towards the later rounds it got really fast-paced and this made it so much more fun since I barely had time to think.