The Shopkeeper sells upgrades in the shop. After completing the linear portion of the game, more upgrades become available. "Devil's due" doesn't become available until you die, and "Aerobatics warrior" doesn't become available until you obtain the Wingsuit.
List of Upgrades 
Edit
Linear Edit
| Icon | Upgrade | Effect | Cost |
|---|---|---|---|
 | Karuta Plates | +1 HP | 30 |
 | Energy Shuriken | Shuriken | 50 |
 | Strike of the Ninja | Attack Projectiles | 40 |
 | Second Wind | Air Recovery | 80 |
 | Serendipitous Minds | Enemy Ki Drops | 200 |
 | Serendipitous Bodies | Enemy HP Drops | 200 |
 | Path of Resilience | -1 Damage Taken | 1000 |
| | Kusari Jacket | +1 HP | 320 |
 | Prepared Mind | +1 Ki, +1 Pierce | 250 |
 | Currents Master | Underwater Dash | 250 |
 | Aerobatics Warrior | Glide Attack | 150 |
 | Meditation | Checkpoint Restore | 550 |
 | Devil's Due | 50% Death Fine | 400 |
Second Quest Edit
| Icon | Upgrade | Effect | Cost |
|---|---|---|---|
 | Rejuvenative Spirit | +1 HP, Potions Fully Heal | 350 |
| | Centered Mind | +1 Ki, +1 Pierce | 350 |
 | Demon's Bane | Triple Damage on First Attack | 2000 |
 | Time Sense | Adds Timeshifts to Map | 250 |
 | Power Sense | Adds Power Seal Counter to Map | 250 |
 | Focused Power Sense | Marks Power Seals on Map | 250 |
Item Management Edit
When doing Speedruns of The Messenger, it is strongly advised to constantly obtain Time Shards. You should not go out of your way to obtain Time Shards, but you should collect every Time Shard possible throughout the entire game. Here is a list of the upgrades when you need them, how much they cost, as well as optimal spots to purchase the upgrades:
- First shop in Autumn Hills: You should have 40 Time Shards to purchase "Strike of the Ninja," which allows you to attack projectiles.
- Final shop in Autumn Hills: You should have 130 Time Shards to purchase "Energy Shuriken" and "Second Wind." The Energy Shuriken will allow you to do a one cycle kill against the first boss, the Leaf Monster. Second Wind will be useful for the rest of the game.
- First shop in Howling Grotto: You should have 275 Time Shards to purchase "Currents Master" and "Aerobatics Warrior." Currents Master is useful in many areas of the game; anywhere that has water since it allows you to dash in water. Aerobatics Warrior is useful for the rest of the game because it allows you to attack downward while using the Wingsuit.
- First shop in Searing Crags: You should have 230 Time Shards to purchase "Karuta Plates" and "Serendipitous Bodies." These upgrades add an extra hit point to your life, as well as making some enemies drop health upgrades. Both of these upgrades are useful for the rest of the game to help you avoid Quarble.
No other upgrades are required for the 8 Bit and Linear Speedruns. While additional upgrades may be purchased, any additional shop visits can cause you to lose time in the Run. Additional upgrades are not required unless you plan to do longer Runs such as Any% or 100%.
Additional upgrades should be purchased as the Runs continue, and additional upgrades are based on Runner preference and Time Shards collected. Most Runners will stop only 2-3 times during the Second Quest to purchase upgrades for Any% Runs, while 100% runs require all upgrades to be purchased.
The upgrades that should be acquired in an Any% run should include all of the items on the lower-left side of the upgrade tree, which includes: "Path of Resilience," "Kusari Jacket," "Serendipitous Minds," "Prepared Mind," and "Meditation." The other items are not necessary to do a successful Any% Speedrun.
