The game is nice and fun, but there are some points to improve
- It would be nice to have some juicy fx for active reload (camera shake, sfx, something else perhaps) and to give temporary buff to the player after it
- Difficulty curve needs some balancing, because. firstly, after getting the second weapon, there is no need to buy ammo anymore. And secondly, player gets more powerful over time, while monsters stay mostly the same. After several waves monsters don't really pose any danger
But anyway, great work!