I'm not sure that all highly rated games warrant a sequel, even in the world of flash where a great game gets maybe a few weeks of fame. And in the case of Upgrade Complete 2, "more of the same" is unquestionably a strange thing to ask for. More upgrades means more things you can make better, means more things which aren't very good to start with. Upgrade Complete 2 starts out a worse experience, and doesn't really go beyond the original vision to stand out as a true sequel in the end. I would've very much liked a "harder enemies" upgrade or a "you can now actually die" upgrade.
For a game that wasn't designed to be fun, Upgrade Complete 2 behaves exactly as advertised. If I were to rate it not on its incisive commentary but as a game, I wouldn't be able to give it more than a 2/5.
I like where you're coming from. I hold my opinion on how well you've implemented a generic shooter. The customized ship mechanic is cute. 3/5 I would have wanted to buy a boss fight, a highscore table, and BADGES. I would so want to buy badges.
The only thing that would make this snake better is if you didn't traverse the surface of the cube but instead the volume. I'm hoping you've figured out how to do this.
This is a game with very appealing graphics and a well-implemented idea. The things that make me unwilling to play it (a fifth time) is that I have to wade through 10 or so unexciting levels before I can get enough things onscreen at once to make going for an 100 kill combo entertaining. The other issue I have is that the explosions end up obscuring bullets--and I keep an eye out for bullets-- and sometimes I won't know what direction a bullet that happens to get caught in the explosion will be coming out of it in. I just can't see it. It would be good to either have explosions of ships do damage to everything (and catch bullets) or for the bullets to be visible over the explosions some how.
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 "UPGRADE COMPLETE!"){kind=icon}
 "SnakeBox"){kind=icon}
 "Dodge"){kind=icon}