Good, but it needs work
I have some suggestions that could improve this game:
1) Make the color of the font that shows you how high up your shot is a more readable color. Currently, it's impossible to tell how high it is whenever it passes through the white part of any gauge.
2) Work on the teleport. Try to have it so that it teleports you a minimum distance. I tried using two of them in a row, and both times I landed within an inch of where I started.
3) Fix the win screen. After successfully blowing my other self up in 4 player mode, the game just continued. I also played in one-on-one mode, and when I finished there all the game did was display the message for a height bonus, and then lock up.
4) There seems to be a little problem with the boxes that scatter themselves across the playing field. I'm not entirely sure how, but some of them managed to get lodged deep underground after a few shots. You may want to look into this. Also, it wouldn't hurt to tell the players ahead of time what the boxes do. I manged to figure it out, but there are some people who are dumb.
As for weapon suggestions, you may want to try emulating things from the original Scorched Earth, such as shields and spreading bombs.