What I liked about the game from most important to least important:

* The gameplay was challenging. The challenging gameplay and the tension that I felt when a lot of enemies starting coming in made this game feel fun. I really like how each match starts easy, but then becomes harder as time goes by.

* The rules of the game were easy to understand. Once I learned the controls, I easily learned the rules of the game. I was able to finish the learning phase of the game very fast and get to the fun portions of the game.

* I liked the gameplay mechanic in where the harmless enemies become harmful and the harmful enemies become harmless. One concept that I appreciated about your game is that rather than trying to do something very simple and easy to do for the core of the game, you tried to make the game's core more interesting and creative. This mechanic adds a layer of strategy and depth in this game. In the game, the player must have strategy to know when to kill a harmful enemy so that a harmless enemy doesn't immediately damage the core when becoming a harmful enemy. This added layer of strategy makes the game more fun for the player.

*I like how each match of the game starts. The beginning of each match allows the player to be launched in the game. Also, in the beginning of a match, there are not many enemies. I like these details about the beginning of the match because these details allow the player to feel relaxed and give the player a break after losing a match. In this way, the player can become more aware of the current surroundings and can perform more efficiently in the match. This makes the game more fun for the player.

Some concepts I do not like about this game from most important to least important:

* This game needs more UI elements and scenes. This game needs a Main Menu, a Credits, and a How To Play Scene. Adding multiple scenes in a game can make the game look more professional and polished. Making a game more polished can make a player more immersed into the gameplay experience and can make the player happier with the game. Also, this game really needs a How To Play UI screen even though the game page explains the controls. This is because a player might forget the controls on the game page while playing the game. For example, when I was playing the game, I forgot which buttons I could press to launch off. Also, having the instructions of the game not be told in the game and rather told on a game page is considered unprofessional today. This can ruin player experience and immersion into the game. By adding a How To Play UI screen, players can learn how to play the game quicker than by reading the game instructions on a game page and can get to the fun portions of the game more quickly. 

* The player's movements needs to be fine-tuned. The player moves way too fast in this game. This is frustrating because it is hard for the player to control the player's character. This makes the gameplay unnecessarily frustrating as more ships are more likely to damage the core since it is hard for the player to control the character to hit the ships because the movement is way too fast.

* There is a lack of audio in the game. First of all, having a soundtrack would really give the game a mood, have the players feel something, and care about the gameplay experience. In addition, listening to a soundtrack that is good is nice and can make a player feel happier with the game. Having some sound effects would also be a nice touch of polish and the sound effects can help the player be more immersed with the gameplay experience. In addition, sound effects can also help the player with the game. By using sound effects, you could give the user audio cues of what is happening during the gameplay experience. For example, if a sound effect that is played when the core gets hit by a harmful enemy is played during gameplay, the player knows that the core got hit by a harmful enemy.

*There should be boundaries in this game that restrict the player from going off screen. This is because once the player goes off screen, it is hard for the player to come back on screen again. This is because the player can not see the player's character, and therefore it is hard for the player to come back on screen in a timely manner. The fast movement of the character in this game makes it even less likely that the player will be able to get on screen in a timely manner. The farther away the player travels from the screen, the greater the chance that the player will not get back on screen in a timely manner. If the player can not get back on screen in a timely manner, the harmful enemies might be able to destroy a defenseless core. 

The game seems to run a lot faster in my computer than in your gif. It makes it really hard to play right now, tell me if you know what could be the problem! I really want to properly play this game.

Simple, engaging, made with Love, what more to ask for :D

Either the game drastically slows down once it gains focus or my computer can't handle it on full speed. With my i5 and GTX 1050 this is quite astonishing.
Because of that, I couldn't see precisely if the difficulty ramps up over time, but it didn't seem so.