Time boxing and a bug a day
A game in a pre-alpha version has so much left to do, that it is really hard to release it. But with this attitude I would never release it at all, trying to remove all kind of bugs and glitches while adding new features on-the-fly.
Therefore I'm using a time management technique called time boxing. That is, more or less, to set a fix time frame (this month) and try to approach your goal as close as possible, but after reaching your deadline, stop and be happy with the result.
Therefore I'm currently not adding any more features, any feature which is not in a worthy state, will be disabled and I will remove atleast one bug or one glitch a day until release. The latter has the disadvantage, that the nights get quite short when not solving a bug, but hey, that's the reason coffee had been invented, isn't it ?
So, stayed tuned...