If there's one stand-out feature about this game, (and to be fair, it applied to your game last year as well) it's the attention to detail you put into it. The gameplay loop itself is fairly simple, but upgrades in between waves really help to keep you invested for a decent amount of time.
[Spoilers ahead]
I think the whole cracked game thing is really interesting, and really adds to the experience of playing a dodgy pirated game from the early 2000s. I legit had to run a virus scan after I used the crack. The documentation attached, along with the terrible music etc all helped to build the impression. For some people, it might seem like too high a bar of entry to go through the process. After all, no-one enjoys pirating video games. However for me, I just found it very intriguing, which helped me to suspend my disbelief and go on with it.
The whole dual-currencies thing is also something that isn't funny in itself, but the humour comes from how far you take the joke. Leading the game to your website was a nice touch. I played the game for a second time using the infinite coins hack, just to see how far I could go. Turns out that after you reach about 50 guns, it kinda has the reverse effect and the rate of fire actually gets a lot worse. Even so, I carried onto 128+ guns, and used up the (luckily unlimited) ammo like no man's business.
Unfortunately my portable DVD drive wasn't working for whatever reason, so I couldn't play the game to the Mario 3D world soundtrack, like I was hoping. However, I assume it works fine, and it's another great example of your attention to detail.
This kinda game is usually somewhat boring to me, but everything you have done around it has elevated the game to another level. It's a really commendable effort, and you should be very proud of the final product you have made in such a relatively short amount of time.