Do not download the ROM from random websites. Instead, buy the game on modern hardware to support independent developers. If you absolutely must play it on a 3DS, buy a used physical “download code” on eBay (though these are rare and expensive) or legally dump your own digital purchase using a modded console.
Running an open-world game with destructible environments and dozens of moving entities on aging 2011 hardware was a challenge. The 3DS version ran at a lower framerate than its console counterparts (targeting 30fps, often dipping during heavy action), and the resolution was naturally lower. However, the developers optimized it well enough to make it a playable and enjoyable experience. shakedown hawaii 3ds rom
If you have a modded 3DS, play the ROM there. If you only have a PC, buy the native PC version on Steam instead of emulating the 3DS version. The Steam version runs at 60 FPS with no emulation glitches. Do not download the ROM from random websites