A red coin, if you collect 8 (by default) of them, you get an item as a reward (flower by default). It also plays a sound effect, and it doesn't overwight the item box.
Inspired by NSMB's red coins.
Added SA-1 support, a way to change the amount of coins to collect for the reward (+/-), optimized the code and made it more user friendly.
There's now a different issue with the sound effects - it's coded that if the SFX value + the current freeRAM value is greater than or equal to #$1A, then it will just play sound effect #$19. This makes it impossible to use effects #$1A+, regardless of how many coins have been collected. There's really no need to compare the sound effect value against anything - Just check the value of the freeRAM, and if the required coins haven't been collected yet, just add the current freeRAM value to the base SFX value and play it.
There's also a missing |!addr define for $0DC2, which on SA-1, results in a copy of the item currently in the item box being dropped (or nothing if the item box is empty), instead of the user-defined powerup.
Please test resources thoroughly, both to ensure there aren't any bugs and to make sure it works properly on all the formats it claims to support.
Additionally, there's still an instance where you're using BRL to jump to another part of the code. BRL is usually only used when jumping a greater distance (e.g. to different codes), and even then, JMP is better for that. For jumping short distances like in your block, you can use BRA, which is smaller in bytes and usually slightly faster.
This on it's own wouldn't be a rejection reason since it's only one BRL and the speed loss is minimal, but it's something worth knowing.