Hardmode

Hardmode is a different difficulty level that can be accessed after the player goes through the tower base. After falling off the tower the player starts climbing it up again, with several differences, listed below.

It is hypothesized that the more times you fall out of the tower to the Tower Base, the harder stages will get, by spawning in Elite Bots / Terminators more often, decreasing stun time, and increasing enemy spawn rate.

Enemies

 * All starting patrol bots are now laser patrol bots (regular patrol bots still spawn normally);
 * All cameras are now laser cameras;
 * All sentinels are now laser sentinels;
 * Elite Bots can now spawn in all levels;
 * Terminators can now spawn in all of the Gray levels.

Game mechanics

 * Stunned enemies take 30 rounds to recover instead of 32;
 * Enemies now spawn quite faster: they take 60 rounds instead of 75;
 * Any shopkeepers that you've purchased items from disappear;
 * If you purchased keys from the shopkeeper at level 11, it will keep its escalating prices for new keys you purchase now - for instance, if you bought two key playing normally (for one and two gems each), the first key you purchase in hardmode will cost three gems (caps at five gems/key)