The first time I played, I got totally destroyed as the people above indicate. The second time, I bought some upgraded weapons before starting, and I was pretty much unstoppable - I lived through 8+ waves with no problems, barely taking a hit, and adding more and more stuff in the store. So, there may be some difficulty balance issues there. But I had a lot of fun; tons of bullets, cool upgrades (but not so many of them- I maxed out fairly quickly), and a really cool look with the vector-style graphics. The sounds were good too. I really didn't see much impact from the shuffling of the enemy types - the only ones that gave me trouble were the ones with all the cannons, and those weren't bad unless they lived long enough to start shooting, which they seldom did when I was upgraded. Really fun, action packed even for a small screen, but I think it's a bit too easy, and after a few levels, the enemy AI becomes pretty obvious. Totally great for a 48-hour project, though - I'm just making suggestions for further work.