Both special coins are mandatory for the final key vault in Hideout Helm. Ordinary Banana Coins cannot replace them. Earn the Nintendo Coin from DK’s arcade machine in Frantic Factory and the Rareware Coin from Jetpac in Cranky’s Lab.
Nintendo Coin — finish the arcade twice
Enter DK’s arcade room in Frantic Factory and activate the machine with the bongos. Clear the four original Donkey Kong boards once to receive the Golden Banana. Play again and clear all four boards a second time for the Nintendo Coin. The banana alone does not satisfy Helm’s coin door.
Arcade survival
On the barrel board, choose ladders with time to react instead of racing directly under rolling barrels. On the rivet board, remove rivets while watching fireball routes. In the elevator board, watch the spring pattern before the last climb. In the conveyor board, allow moving hazards to pass before committing to a ladder. Restarting after losing all lives requires another complete run.
Rareware Coin — unlock Jetpac
Collect fifteen Banana Medals, then speak to Cranky to access Jetpac. Reach 5,000 points and collect the Rareware Coin when it appears. Do not quit at the score threshold: the coin must actually be picked up.
A safe Jetpac route
Stay on the first stage if you want a predictable scoring loop. Shoot approaching enemies and collect the valuables they drop. Assemble and fuel the rocket when convenient, but there is no need to rush into later stages just to reach 5,000 points. Watch the screen after passing the threshold and fly to the coin.
Final vault check
Bring both coins to Hideout Helm after disabling the machine. Four crowns open the first door; the Nintendo and Rareware Coins open the next. Photograph the two fairies inside and take the eighth key.