I really wanted to like this game. Being able to explore different planets in the solar system, each with their own "things" (like differing "gravity" levels) appealed to me a lot in a Metroid sort of way, and the platformer engine is bearable for the most part, but there are some plain sloppy issues here.

The palette and charset for Venus are missing entirely (you can edit the game and save them, though). The boss on Mars breaks and goes out of range if you shoot it too fast, and I couldn't damage the boss on Venus at all.

There is a boss on Mercury, too, but I couldn't figure out how to beat it--at that point, the demo ends. Yeah, it's a demo. Belch! There's some stuff on Jupiter, too, but I didn't put much effort into exploring it. There's cool stuff here, but overall, Space Jam 2 isn't very fun to play and isn't very well polished. Would not recommend, sorry.