Thanks, Alvin! Let me tell you, I tried for hours (at the cost of play-testing) to get this to run in the web. I got some weird error and still haven't figure it out. I'm going to keep trying though.
The upgrade issue that you are experiencing is a bug. I've already fixed it on my end, but will have to wait for the game jam to end before I can upload the changes. In my testing, you actually DO keep all of your upgrades, the prices just drop and the buttons re-appear in the shop as if they have never been purchased. Some of the upgrades are so incremental that you don't realize you've kept them, but they should be there. For example, if you buy the auto-shoot, then die and "try again", you'll still have the auto-shooter, but you'll also be able to "buy it again" at the original price. Buying it again just takes your money, but nothing actually happens. However, buying something like blaster damage, will carry over and buying it again will continue to increase the damage value.
What should happen (at least until I get a save system) is that when you die, all upgrades carry over, but the prices in the shop DO NOT reset, they remain at the price they were before you died.
Anyways, thanks again for playing and for the great feedback. I really do appreciate it! I do plan on continuing development because there's just so much more that I want to do. I just didn't have the time.
Oh! Have you experienced the issue where you get stuck after destroying a planet? The blocks will be gone, but the game won't move you back to the planetary map. If so, press "Ctrl + D" to open the debug menu then click "complete level". I originally was going to keep the debug menu a secret, but this is a pretty bad bug, so I figured I'd tell everyone the cheat codes, at least until I can upload the fixed version. :D
Cheers!