How do I upgrade my tank?

I am playing Diep.io and I would like to know how to become another tank in Diep.io.

For example, I see an Overlord and would like to become that tank.


Solution 1:

In the top-left corner, you can select which tank you can upgrade to. As a Basic Tank, you'll most likely see this:

Basic upgrades, not including Smasher

If you reach level 30 as a Twin, you would see a different list of upgrades.

Twin upgrades

If you press the gray Ignore button below the upgrades, the Upgrades menu will slide out. It will return again if you hover your mouse near the top-left corner. It will also automatically reappear if you reach levels 30 or 45. If it will not appear even when hovering your mouse near the corner, it is probably because you don't have any available upgrades.