A fine game
I will try to provide constructive criticism. Let us see how it goes. Ignore the low rating, it means nothing.
I liked the game but I would not have played it if it had no medals. It did not catch my attention. You just jump around. There is nothing interesting to keep me playing. I do not care about scores because hackers and really good players ruin the fun. Scores are something from the past. Now people are into things like medals and achievements. So I suggest you to had more. Examples include reaching a certain height without double jumping or shooting every small block that appears until a certain height. Now those would be some good challenges/medals. Something to keep people interested. Not to mention the best thing would be actual levels and variation... You know, a full game? This is more of a mini game. (Nothing compared to the greatness of Tetris by the way.) My main suggestion is for you two to make a complete game with everything you can think of. Probably more important, it needs something to keep me playing. Whether it is levels, medals (you can still add them) or something else. I am not saying you did bad, the game is OK, in the end I liked it to the point of reviewing.
As for the artwork, I do not like "pixalated" graphics but this is different. I like this style. The colours fit well together. I have no major complains except for the font and the variety of blocks, backgrounds, and so on. I had trouble reading the text, it was too small. Newgrounds has an option (top right corner buttons) for the game resolution to be expanded. You could make use of that. But it is "grayed" out...
As for the coding I unfortunately can not help you, I can only point out bugs which is not so useful. I found several. If you are interested in knowing details just ask. There are problems entering the players' name, blocks smash me when they do not even touch me, later on the game the blocks stop being aligned and start being supported in the air, a tower is usually formed on the left and so on.
Since this is a simple game the game-play is also simple. I would like the game to start right away after I press the Space bar, I would like to be able to shoot while jumping. I would like customization of controls too, something that all games should have. Please consider learning how to do it so you can include it in all future games. Due to the variety of keyboards and styles of playing you must provide an option to change the controls. Other than that the game-play seems fine.
The music suited the game so well. You should have included it in the credits. Everything is to be credited. I would want a longer theme if the game had more to it. I suppose the sound effects were OK but the jump sound is annoying. All games should also have separated options to turn off sound effects and music instead of both together. At least you do have one option...
I enjoyed details such as rocks falling in the background with the screen shaking and dust when a block settles. The signs at the start are good, there should be more. I would want to go higher just to read them. Something bad is the pause system. You did not make it. I have seen the same pause system in other games. It has problems. The game unpauses automatically (causing me to lose) when I return to the window. It is annoying because it does not do what I want. It also looks too much "pixalated". P to pause is not in the instructions.
Well this is it. Focus on anything I said that does not apply to this game only so that maybe you could improve in the future. Sorry that I pay too much attention to details. I even tried not to mention them all.
Good work.