This game has a lot of stuff, well done for making all this in 72h! Dialogue system (with cool wobbly text), intro and outro, a tutorial, a whole inventory drag and drop management system, some audio, enemies with varying hitpoints, sizes, and speeds, and more. And it works well too! I do however agree with other people that the controls for shooting could be improved, but especially moving while shooting. Felt a bit clunky to stop shooting, turn around, run away a bit, then start shooting again and hope the enemy dies before it reaches you again. Also being able to reload while not being in the "shoot mode" could be a good addition too. I don't think the system is fundamentally bad, it could definitely work, just needs some tweaks so it feels snappier to use.
Another thing I thought about is the usability of the inventory system. Right now it doesn't really serve a purpose except for being a cool thing. It would be nice if you integrated it in some way, like for example giving the player loads of weapons so that they have to select which ones to carry, or perhaps a weight counter in the inventory and then making the bridge require your inventory to be below a certain weight to able to cross, or something of the sort. Or to spitball more ideas, having pickable items that are essential for progressing the level take up a lot of inventory space so you have to juggle and manage your inventory a bit more. You get the idea. Just something to make the drag and drop inventory system more of a used feature in the game :)
Overall really nice work, I don't think I've ever had time for a whole tutorial as well as intro/outro in a ludum dare yet. Impressive stuff :)