Here's a plot spoiler:
Dark Samus is Metroid Prime (at the end of MP1, that hand was the hand of ds).
i like the limitless ammo of MP1 as well as the sustained blast wave cannons (Wavebuster! Zzzzzzzzzzzzzz...), but
MP2's enemies are quite different in thinking and attacks (although there seriously needs to be some more kick@$$
space pirates, Elite Pirates RULE).
The multiplayer in MP2 needs more different units (like playing Elite Pirates or Dark Samus, scattershots that have good
chance of hit are better than a big shot that's easy to avoid).
Cannons in 2 are cooler (although the Annihilater needs to be stronger; something like as strong as a charged power beam
shot with charged AB being as strong as a super missile).