The best replacement for metroid is halo.

The best alternatives to metroid are rated as following:
★★★★★  halo
★★★★  megaman
★★★  zelda
★★★  master chief
★★  super metroid
★  castlevania
★  samus
★  metroid zero mission
★  kid icarus
  bioshock
  shadow complex
  asteroid
  wolfkrone
  killzone

Your alternative for metroid is not listed? Suggest!
Speaking about metroid, one probably shouldn't forget about wii zapper.

Other search terms related to metroid and their ratings are:
★★★★★ wii zapper
You have in mind a companion for metroid and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of metroid in all years. Click on graph for more.
metroid
halo
megaman