Depends on your target audience. I think as an arcade shooter, you're pretty much safe to do the beta version.
I've found that any little minor issues that might pop up in a beta version will probably (annoyingly) put people off the final version.
But if you're doing an "arcadey shooter", your audience is probably well aware of exactly what "beta" means, and will be more open minded.
Just be sure that your final version is worth it, otherwise folk probably won't be bothered to upgrade from the beta.
I agree with what Jayenkai said. It also might be cool to give some reward to those who were in the beta if they buy the full game. Secret ship, $1.00 off purchase, or something like that :)
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