Game was a bit confusing when booted up. I guessed that it was a WASD game, and happened to come across the roll button while testing a few random ones. These were obvious enough I suppose, but it was odd to have to figure them out BEFORE the tutorial, which teaches you to use them.

The graphics and art style are very nice. The player and enemies contrast really well with the background and even though the flying enemies are similarly colored to me, I never lost track of my character.
The animations and movement are responsive and fluid. The rolling gives a great sense of mobility whilst not making you too fast for the enemies.

First big problem - when I walked into the first room, I accidentally skipped the first slide of the tutorial because I was pressing W to walk through the doorway. I suggest using a separate button or the mouse to advance the tutorial.
The tutorial itself needs a few improvements. A reading-based tutorial might not be the best option for this game. Although the controls are simple, the mechanics of the game are just slightly confusing when explained in text. I figured it out without too much confusion, but I'm worried that it might be a bit too vague for others.
The highlights on the doors and enemies during the tutorial were not noticeable enough. I didn't really notice the doors/enemies colors until I had gone through the full tutorial. You may want to highlight them even more, or add arrows pointing to them.
I also missed the attack button when the controls were presented - it blended in too well with the numerous amount of controls on screen. Making graphics would probably work best here, such as an XBox controller/keyboard with the functions of each button labeled.
There were also some phrasing issues and grammer mistakes. For example, "Each room have a number of enemies that you have to kill, in which their body it's placed an Orb with one of the 3 primary color." is very poor English. Have should be has, etc.

I was surprised how much depth this game had. The enemies were usually pretty easy but not too easy, which contributed to a really nice feeling of urgency to remember the colors of the doors and pay attention to the colors of the enemies. As the enemies get harder and rooms started to take longer, the doors got harder to remember, and the colors of the enemies hard to creep track of. This was great because it lead to me fighting against my own memory, rather than just the enemies. This is where I feel the game is strongest. Although its annoying to finally beat a hard room, only to realize that you forgot the door colors or didn't pay attention to the enemies' colors, its equally satisfying to go back and try again, assuring yourself that you won't forget this time.
Additionally, I found that as I played more, new and fun strategies opened themselves up. For example, on the easier rooms, you could clear them quickly by remembering one door color, and making sure that the last enemy killed was that color. However, if you choose to do that, you run the risk of being forced to/accidentally killing the last enemy of the color you needed. That was lots of fun!

The boss fights were very odd. I must admit, I only ever beat one boss during my play, and promptly died afterwords, but I noticed that the charging boss was much much more difficult than the shooting boss.
Additionally, the boss fights didn't fit into the game very well. They ignored the main theme of memory and colors.
Health indicators would have been nice, as the bosses take much more hits to kill than anything previously in the game.

The levels could have used a bit more complexity. I feel that if you were to randomly place walls in each section, it would add a lot to the game. At the moment, the sections feel very empty, except for later in the game when there are loads of enemies in each section.

Minor annoyances:
Health pickup sounds were very loud and high pitched.
XBox controls worked very poorly.

Obviously the game lacks progression, but even in its current state its still quite fun and difficult in a unique way.