Throughout the game, you will have an opportunity to use the money that you scoop up from defeated enemies to purchase upgrades for Opa-Opa. In order to buy items, you must locate the Shop balloon. When you see one, collide with it to enter the shop. The Shop balloon will not remain in the stage forever. If you do not visit it, it will return to the sky after a period of time, only to return later on. You keep all items that you purchase from the shop until you lose a life.
You can buy as many engines, weapons, and bombs as you can afford to. However, only one of each item can be active at any time. Engines do not wear off, but weapons and bombs do. When they do, you automatically revert to your original default weapons. In order to activate any weapons or bombs that you have in reserve, you must find and collide with the yellow Select balloon. When you do, the weapon selection screen will appear to briefly allow you to configure Opa-Opa.
Engines[edit]
Each of these engines increase the speed of Opa-Opa. The increase in speed correlates to the price of the engine. The price of the engines do not increase, regardless of past purchases.
| Item | Name Price |
Description | Effect |
|---|---|---|---|
 |
Big Wings $100 |
This item increases the size and effectiveness of Opa-Opa's own natural wings. Though they provide the lease increase in speed, this engine upgrade should be purchased at the very minimum. | 
|
 |
Jet Engine $1000 |
The Jet Engine is the first engine replacement for Opa-Opa's wings. They give Opa-Opa an appreciable boost in speed, certainly enough to safely dodge many boss attacks with ease. This engine is highly recommended. | 
|
 |
Turbo Engine $10000 |
With the Turbo Engine, you begin to sacrifice control precision for speed. Truly you will have no problem zipping around the screen, but you may have difficulty stopping in time to prevent a collision with another fast moving object. Buy this engine sparingly. | 
|
 |
Rocket Engine $100000 |
Not only is the Rocket Engine prohibitively expensive, it makes Opa-Opa nearly impossible to control. Even a little nudge sends Opa-Opa flying. Purchase of this engine is not recommended. Use the money to buy extra lives instead. | 
|
Shot Weapons[edit]
When you purchase a shot weapon and activate it, you will be able to use it for approximately 20 seconds. After those 20 seconds are up, you will lose the weapon and revert to the default Twin Shot. Each time you purchase a weapon, its price will increase by the amount shown in parentheses.
| Item | Name Price |
Description | Effect |
|---|---|---|---|
 |
Wide Beam $500 (+ $400) |
The Wide Beam weapon allows you to fire a bullet that is nearly three times as high as Opa-Opa. While it's easier to hit enemies with such a wide shot, its destructive power is the same as the Twin Shot. | 
|
 |
Laser Beam $1000 (+ $800) |
The Laser Beam is an intensely powerful weapon. You can hold the fire button down, and the laser will continue to extend from Opa-Opa to the end of the screen. As a result, it will continuously pummel enemies that it hits and destroy them quite quickly. It's not very thick, and the thickness decreases as the remaining time to use the laser runs out. | 
|
 |
7 Way Shot $5000 (+ $4000) |
This weapon gives Opa-Opa the ability to fire 7 bullets in a wide pattern that fans out. Each bullet is as powerful as the Twin Shot, so if all 7 bullets are fired upon an enemy at close range, they will do a substantial amount of damage. The price of this weapon increases dramatically, making it difficult to purchase more than once or twice. | 
|
Bombs[edit]
Except for the Twin Bombs, when you purchase bombs, you are buying them one bomb at a time. You can hold up to ten of any type of bomb. After selecting a particular bomb, you will revert to the regular bomb until you visit a shop or hit the Select balloon.
| Item | Name Price |
Description | Effect |
|---|---|---|---|
 |
Twin Bombs $100 (+ $100) |
The Twin Bombs item gives Opa-Opa the ability to toss out two bombs at a time instead of just one, doubling his bombing effectiveness. It never runs out unless Opa-Opa is killed, and at such a low price, it is a must-buy. | 
|
 |
Fire Bomb $2000 (+ $500) |
The Fire Bomb is a bomb that explodes with a fiery blast to the left and right when it hits a target. It does a lot of damage to whatever it hits, and the blasts go on to destroy anything that gets in their way. It is difficult to use effectively, but it's price rises the least out of the three special bombs. However, you can chase one of the flames all the way across the stage and watch it cause substantial damage to enemies. | 
|
 |
Smart Bomb $2000 (+ $1000) |
Smart Bombs instantly damage every enemy on the screen. As a result, there is no visible effect beyond the destruction of small enemies and bullets. It has the same strength as a single Twin Shot, so it's not effective against bases or bosses. It should be used as a way to rescue Opa-Opa if he is surrounded by small enemies or bullets. | |
 |
Heavy Bomb $2000 (+ $1000) |
The Heavy Bomb is the probably the most effective bomb. It crushes bases and is quite effective against a number of bosses. It drops from the sky, and has a tendency to fall behind Opa-Opa so it is important to position him correctly before using it. (The 16t indication on the side is a reference to British sketch comedy show "Monty Python's Flying Circus). | 
|
Extra Ship[edit]
| Item | Name Price |
Description |
|---|---|---|
 |
Extra Ship $5000, $20000, $50000, $100000 |
You will not earn extra lives by reaching particular scores. Instead, your only means of obtaining extra lives is to purchase them at the shop. The initial asking price is $5000 (settable by arcade operators through the DIP switches) and increases dramatically for each ship, up to a maximum of $100,000. |