Thank you, everyone, for all the comments, eitehr positive or negative.
I wasn't happy with this theme at all, and I didn't have as much fun making this game as I had while making my other entries. However, I did the best that I could while also having a tiny bit of fun. I would have loved making the game more complex, but I started making the game itself a bit late due to problems with Unity.
@Nobuyoshi I was having a few troubles with diagonal movement which I wasn't able to fix without using too much of my precious time.
@TheMonsterFromTheDeep At first, I made the enemies go after you instead of the base, and I didn't think about putting it back in for some specific kind of enemy.
@Foolmoron Yes, I know that they should spawn in different spots, but again, my motivation for making this was quite low.