From Brotato Wiki
Materials
In Brotato, Materials are small green objects that are dropped by Enemies when they are killed. Harvesting also grants you matertials at the end of each wave.
When you gain materials, you gain both XP, used to level up, and Gold, the currency used to reroll and buy items in the Shop
Within the game, there is no clear distinction between Materials and Gold, and the terms are used interchangeably despite functioning in two different ways. We make the distinction here on this page to make things more clear. The rest of the Wikipedia uses the terms in the same way as the game does.
XP
XP, or experience is used to level up. You can see your level and see your progress towards the next level in the top left corner by the green bar.
Whenever you Level Up, you gain +1 Max HP 
and you an Upgrade at the end of the wave.
You can increase your XP Gain with certain items such as 
Scar.
Some Characters gain more XP, like 
Mutant, while others gain less, like 
Lucky
The Experience required to level up is:
XP Required = (Level + 3)*(Level + 3)
This means that the first Level Up requires 16 XP, or 4x4 (from level 0 to level 1), and getting to level 2 requires 25 XP, or 5x5.
XP Diminishing Returns
Since the required XP for the next level scales to the second power, buying an item that boosts your XP Gain, such as Scar, doesn't increase the amount of levels you gain by 20%.
For example, if you over the duration of a game would reach level 22 (5511 XP), starting with a Scar would instead mean you gained
Chance for a Baby Alien to drop a Loot Crate: 1% * 1% = 1/10000
5511*1.20 = 6613 XP
This is only enough XP to reach level 23, and about halfway towards level 24. So buying Scar didn't get you 20% extra levels, but rather about 1.5 additional levels.
Mutant on the other hand could in the same example expect to gain
5511*(100% + 200%) = 16533 XP
Which is enough to get to level 33. Notice that the Mutant has an XP Gain that is the same as 10 Scars, yet only gains 11 additional levels. But we saw that the first Scar gave 1.5 Levels. So you've expected 10 Scars to give about 15 levels.
This showcases the diminishing returns you gain on increasing your XP Gain.
Gold
Gold is the currency used to reroll Upgrades and items in the Shop. And it is used to buy items in the Shop. In the game, the currency is just referred to as Materials.
| Level | 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 30 | 40 | 50 | 100 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| XP Required | 0 | 16 | 25 | 36 | 49 | 64 | 81 | 100 | 121 | 144 | 169 | 196 | 225 | 256 | 289 | 324 | 361 | 400 | 441 | 484 | 529 | 576 | 625 | 676 | 729 | 784 | 1089 | 1849 | 2809 | 10609 |
| Total XP Required | 0 | 16 | 41 | 77 | 126 | 190 | 271 | 371 | 492 | 636 | 805 | 1001 | 1226 | 1482 | 1771 | 2095 | 2456 | 2856 | 3297 | 3781 | 4310 | 4886 | 5511 | 6187 | 6916 | 7700 | 12515 | 27420 | 51025 | 369550 |
| Name | Rarity | Effects | Base Price | Limit | Unlocked By | Tags |
|---|---|---|---|---|---|---|
| Tier 3 | +5 % Dodge 50% chance to heal 5 HP when dodging an attack |
60 | 1 | Dodge | ||
| Tier 1 | +8% chance to heal 1 HP when picking up a material -1 Ranged Damage |
25 | 13 | Pickup | ||
| Tier 2 | +3 % Crit Chance +20% chance to heal 1 HP when killing an enemy with a critical hit |
35 | 5 | Win a run with  Lich |
Crit Chance | |
| Tier Item name not found | Item name not found | Item name not found | Item name not found | Item name not found | Item name not found | |
| Tier 2 | Spawns a medical turret that shoots bullets healing 3 (+5% ) HP |
40 | Engineering, Structure |
