Which Alien upgrades should I prioritize to advance faster?

The critical alien upgrades are ‘Cargo Capacity’, ‘Catching Speed’ and ‘Catching Tentacles’.

•  ‘Cargo Capacity’ will allow you to eat bigger and more valuable enemies - and save you precious time in returning your cargo to your ‘Home Base’. 
• ‘Catching Speed’ and ‘Catching Tentacles’ will allow you to catch humans more quickly, and to catch multiple humans at once. This will truly elevate your power! But why stop there? 

Have fun! Experiment with different attributes. 

Each will improve your Alien in unique and interesting ways.