I'm a big believer that every action the player takes should be rewarded with immediate and obvious feedback. That's the nucleus of all discussions about game-feel. "As a player, when I do something, I should see/hear/feel the result."

It's easy enough to make a "cha-ching" noise or say "upgrade complete" when a player selects an upgrade, but some of my upgrades still felt weak. It's time to give the players some additional feedback.

When you get new storage, it will be reflected on your ship.

The second tier storage upgrade makes you feel like a space trucker making deliveries. It even has a little hinge and adds mass.

You'll have to balance that with weapons and engine upgrades to suit your style.