Молодец! (My Russian is bad, but everyone gave you a hard time for English as second language, and it seems like Russian is your first, so I thought I'd put myself out there with the non-primary language!)
Very good game! I started playing to kill time while battling a writer's block, then ended up losing my whole evening. I enjoyed the concept.
Thoughts on improvement:
Have Keys 1-4 mapped to a specific gun. Once you have all the guns, it's a pain to scan through all of them to get to the ones wanted. For example, I like using an assault rifle in general, but sometimes I want a high-powered shotgun or the megagun. If I stopped to scroll through for that, the horde would get too large and nearly overwhelm.
The UFO isn't nearly as nice as the plant, especially since it has a delay between hitting the button and it's actual use. It also has a narrow beam where it works in the very center of the field. This isn't where wizards or archers are, so if they build up, the UFO is useless. Maybe the beam can be a little wider and have a longer period of time where it beams up knights.
A bar to show how far into the wave you are would be nice. That helps to know when to use what skill, especially when you're just hoping to survive.
On the bosses, it would be great to have a health bar above them to give a general idea of how much longer it will take to kill them.
In general, great game. These are just plushy ways to enhance the game. It only started lagging on Day 57 or 58. It was frustrating, but not a big bummer. Wish I could play through the night levels, but I don't have the time. Funny ending... mostly because I feel like I've done that (though metaphorically. I haven't shot any suitors!)
PS: The language wasn't as big of a problem that some people are making it out to be. You got the point across, it was functional. That's all anyone should ask for!