Interesting concept for a game, like the cute graphics and sound. The gameplay is decent, and there is a nice upgrade menu too. Nice!
For some criticism, I'd say throwing the gun without any receiving host is very harsh. The is is already quite hard and it just adds to the frustration. Speaking of hosts, it also feels like changing hosts is just not worth the risk seeing as there is no real benefit of doing so except running away for humans. My. It doesn't help with the fact that without any defence upgrade, a human can pretty much melt you in seconds. My suggestion would be either giving some random bonus when changing host, or at least replenishing health and energy by doing so. I also think the player is very underpowered at the moment, and even with the upgrades, it's very difficult to compete with the humans.
Anyway, keep on developing games and keep up the good work!