The progress you've made by day 2 is amazing to see! Keep it up!
You may already be aware of this but a heads up to avoid a headache down the line with enemy design;
You may wanna look into enemy silhouettes. Basically if you make all of your enemy sprites a single colour and put them side by side do they all look the same? If so it means the human brain will struggle more to tell them apart when playing, and as different enemies will have different AI I imagine recognising what's around you and deciding what needs attention more is important :) A really good example to look at is Doom 1/2 where no matter how messy the screen gets you can easily tell almost every enemy type apart due to their shape :D