Glad you found it fun.
About that space ending, well to be honest I just wanted a nice ending :-P, but still, here are a few theories that could explains what happens:
- First of all, pulling the trigger is what makes you travel back to the future. So after killing Hitler, you would be landing in a reality that no longer exists, while in the second case you're just existing in your new reality.
- If you're still not convinced by the first explanation, I got another one ;-). For now, you just kidnapped Hitler, but until you kill him, there's no confirmation that his rise to power would not happen. What if you decided to drop Hitler back in Germany a few years later?... (I can't imagine what a Hitler with alien knowledge could do!...)
- Ok, that second one is pretty weak. But here's the last theory: Perhaps your existence was never linked to Hitler's rise to power, but just to the fact that Hitler grew up to adulthood. You can draw your own conclusions from there...
One of those explanations is the one I had in mind when I made this game, but feel free to come up with your own ;-)