i was on level 18 then i turned off my computer for a few minutes now i need to start over again. Despite of that happening it´s an awesome game

2 weeks to finally get that last medal, 5 stars for weeks of fun from this pretty simple game.

I can't continue the level. I reached lvl 15 but when I tried to play it again, it's back to level 1

I quite literally beat this game with a sprained hand, meaning two fingers. There's no challenge at all. You can kill any enemy from anywhere on the map, and you have a dash attack that can save you from any fall. I found myself dying because I didn't care enough to stop and kill the enemies. It just felt like a complete grind, as there was no reward upon any action. There's no satisfaction in clearing a level because all of the levels are very easy. There's no satisfaction in advancing to the next level because it's just as easy and just the same as the last. There's no satisfaction in fighting the boss because there's no story and the boss is easy (the boss's attack pattern is based on time so if you rush it you can kill him before he uses advanced attacks). There's no satisfaction in beating the game because there's nothing to boast about. Can you say "Hooray, I have proven my skill!"? Can you say "Hooray, I witnessed the ending of this story!"? You can't. It's only 20 levels anyway. Total game time of 8 minutes.
Good graphics, music, and sound design. Everything else is immensely forgettable. It might have been better if you had lengthened the game and thereby created a meaningful difficulty as well as, you know, difficulty. In other words, it might have been better if you ignored the arbitrary time limit from Ludum Dare. It really seems like most NewGrounds games can be summed up by "It would have been great if it weren't for Ludum Dare".

It's an okay game. You really need to consider using only the keyboard or only the mouse though. Having to use both in the same game doesn't tend to work that well.