It starts with an unbelievable premise and never attempts to explain it (how did he end up screwed behind a panel?). Awkwardly paced and attempted nothing more than framing the usual "we're losing altitude, who do we push out of the balloon?" trope... but in space!
Solid enough cast but you'll just find yourself frustrated by the irrationality of it all. Either abandon reality and appeal to those seeking excitement, or be cautious and considered and cater to those who seek immersion and realism. Stowaway achieves neither.
It might rely too heavily on fan service, but who else could this be for? The View Askewniverse might have more in it than the titular characters, but much like Jay and Silent Bob Strike Back - this is only for the hardcore fans. It leaps from cameo to cameo, pointing at previous work and inside-jokes. So why would a new watcher expect to get anything from this?
For what it's worth, I enjoyed it. I like Smith's work and I enjoy the characters. Objectively is it good? Not particularly. Does that matter? Not particularly.
You don't hit "play" on a Tarantino picture with conventional expectations. I was perhaps surprised at how considered and thoughtful the script is, pacing slowly (but consistently) through a blend of real people and absolute fiction smoothly. It felt like it was building towards making a big point, but instead descends into hugely rewarding carnage - which isn't a criticism. In fact, the payoff for your patience and calmness is for jarringly brilliant (and potentially gratuitous) violence. If this is Quentin's last film, he's going out on a high.
This was touted as "the next great comedy" and spoken of in the same revered tones as those reserved for Superbad. It was okay, but there's only so much mileage you can get from children swearing and not understanding sex. I can't even remember laughing, though I wasn't bored either. Not high praise, but not awful either.
If the first film was an unexpected delight carried entirely by the chemistry of its cast, the sequel answers the question of what happens if you dial that chemistry down by half. I laughed a few times but only left the film understanding why the studio was unwilling to back the project.