Wow, I didn't really think that Alien Hominid or Outpost Kaloki X were that hard. You can just set the difficulty to Easy in AH if you really need it, becuase then you have 7 lives and 7 continues. Also, you just have to duck a lot and learn to charge your gun(something that I could have used when I started playing it). As for Outpost Kaloki X, the first missions were so easy because it was pretty much a tutorial, then you just have to look at your objectives and get them done. Sure, I found it annoying to fail a 30 minute mission once, but you can always just check a guide and get some pointers.
And, even though I got them for free in XBLA unplugged, I would also like to add that I regret Geometry Wars and Wik. GW was kinda fun, but just never got good at it. Then Wik was just kinda boring, and I just had better, more exciting games to play instead.