To me this was a fun aliens game, and dare to claim its a prototype to alien infestation due to how similair they both are.
Also the code system made it possible to mod the game, I think I made a aliens movie version.
I liked the different values each soldier had. When one lost a soldier one had time to rescue him/her in the hive on the level hidden somewhere. Plus for seeing the drop ship and the technology and powerloader and other items spread out. Also love the atmosphere and design of the freighter and the levels. Last levels where you find eggs in the living quarters of the ships crew was fun to see as it was so different, and then one was inside the hive and its just hive resin everywhere.
I always mistook the alrger xenos sprites for preatorians, and thought the smaller ones were drones and runners.
The queen fight at the end is good too and how the queen dies is quite brutal.
Also I prefer this games idea of making all xenos able to spit rather than having dedicated spitter xenos like in aliens fireteam elite.
BTW: game boy color had slightly better hardware than the original game boy, but both were 4 bit consoles, Game boy advance was a big jump to 32bit.
Good game according to me.