The store is very much necessary, and you can access it just by diving into it (hold Z to go underwater). Didn't really have enough time to make a proper tutorial, only the button prompts on the titlescreen, so I'm kiiiiiiinda expecting everyone to read and memorize it :P
Things drawing offscreen is handled automatically, the big resource hog probably is the movement processing (since the game is on a looping arena, I need to loop through everything to see if it needs to loop around - in fact, the shark always stays still in the center of the room and I move everything else around). Not shooting any of the boat riders will tank performance a lot since they tend to shoot a lot (and overall shooting keeps the enemies culled much better than your dash will since you can hit stuff at a much greater range).
Again, it's just a simple jam game, and performance + tutorialization wasn't really a top priority... but thanks for the feedback in either case~ I'll see if I can tweak something in a post-jam version.
