Well... I liked this game a lot. 5/5 without a doubt.
But i have some suggestions: 1) i would like to see smth like health regen 2) i wanna see some lvl UP boost for player, smth like +0,05% fire rate or damage for every lvl up - this way game will become much more REplayable and there will be some interest in survival 3) we MUST have a way to spent all those upgrade point we have after full upgrading weapions and stats - i am sure u will find some good way.
Keep going, 5/5.