A decent submission that meets the requirements of the brief. I think that there is clearly effort that has been put in to make the game enjoyable which is commendable.
The inability to control the height of the character's jump really hurts the experience. Having only one height you can jump to can make getting some of the coins difficult and in turn makes avoiding bombs harder than it should be. Secondly, the game could use some graphical cleanup. Not everyone is an experienced artist (im not, for example) but some research into how to do simple animations or something like pixel graphics could have helped make the game look a lot cleaner and professionally made. Perhaps that may have been a bit out of scale for you, so maybe some primitive graphics (like squares) and working on the jumping aspect would have helped, or vice versa. Finally, consider how you export the game. Is there a better way you could have done so, or does it work for you?
All in all, the fact you have submitted a game at all and clearly put work into it is something that you should be proud of, but take what you have learned from making this game and use that to make the next one even better.