Hi @JoseCuenca, this is really cool, I have enjoyed playing your game, both yesterday and today - currently only got as high as 8,400 points though!
Not sure whether you wanted any feedback or not, but a lot of people ask for it, so I thought I would provide some, hope that’s ok… 
Having the extra lives is great, love the shield effect and power-up… dying is fairly spectacular too!
Nice simple sound effects which work great!
I spotted a typo on your start game screen, you have “defende” rather than “defend” - minor thing…
The speed of the game is fairly intense too, from the beginning etc it’s pretty fast.
How about showing what level/wave the player has got to? I was trying to keep count in my head to see if I was making significant progress (I wasn’t paying much attention to the score).
Power-ups lightning icon is nice, but I think a little hard to see.
Pretty sure my shield lasted longer than 5 seconds, but not entirely sure, only just spotted your note about the duration etc. Yesterday I thought there were occasions where I had obtained a shield but then lost it when the next wave arrived, was going to suggest that the player gets to keep it until it’s destroyed… if you’re going with the 5 seconds duration for the shield maybe it could flash red and play a warning type of sound, as I was a little bit more daring when I had the shield 
Power ups for the players shooting would be nice too! Double-shot, or maybe a triple-shot where one goes forward and two out on angles either side etc…
When the player dies and you click play again you’re taken back to the main menu rather than straight back in to the game.
All in all very nice and I have really enjoyed playing your game, all of the feedback above is meant to be constructive and positive - right, back to try again for the 10,000! 