This is very very fun, polished, and a good use of the theme! If you'll let me nitpick, the game's speed appears to be affected by the monitors refresh rate, so I had to reduce mine to play at a reasonable speed. Also, The tutorial appears to be slightly broken at the end and didn't let me finish the tutorial, so I had to refresh the webpage. Finally, I didn't appreciate the tutorial character making fun of me for dying to the tutorial enemy. I personally didn't mind it too much, but it's generally not a good idea to make fun of your players when they're still trying to learn the game. It's a good way to make them quit.
Sorry for that mouthful, but I wouldn't critique this much if I didn't love the overall game. The spinning combat is really fun with the different playstyles and upgrades, the risk/reward slot machine is exciting, and it's very polished at every aspect. Definitely one of those "how was this made in 7 days" games. 5 stars for enjoyment.